Car will sometimes not start after warm.

jsc9306
225

Asked by Jan 02, 2013 at 08:25 AM about the 1999 Pontiac Grand Prix 2 Dr GT Coupe

Question type: Maintenance & Repair

When i start my car, for the first time during the day- I have no problem.
When I go somewhere and shut it off, sometimes it won't resatrt.
It doesn't seem to matter what the weather is outside, it just does it when it feels like it.
It seems to happen more when I am stopped at a gas station, (not getting gas)- as crazy as that sounds.
When it won't restart, it will turn over and crank and act like it's not getting fuel.
We have checked the coils, fuel pressure regulator and just now replaced the fuel pump.
The car has 192,000 miles on it and is well maintained- tune up, etc..
When it won't start, I have to put the gas pedal to the floor, and it will start.
But when I let off the car, the car will want to die.
I have to keep my foot on the gas and rev it up to keep it running- then it's fine.
Every once in awhile, it will not restart at all.
That's the first problem.
Second one is:
When driving down the road, or after a failed start-
The "trac off" light comes on, and the tachometer quits working.
Any solutions on this?
The car has new hub assy's on the front, with ABS sensors hooked up and in good condition.
I have worked in the automotive business for over 20 years, but this one is baffeling to me.
I have been told throttle position sensor, crankshaft position sensors and all kinds of stuff.
I don't want to keep throwing $ at the car, so I don't know which one to replace first.
Any solutions or similar problems out there?

46 Answers

tenspeed
86,115

Holding the pedal to the floor sounds like the mixture is too rich or it's flooded. Sort of like the ECU isn't getting the temperature signal or maybe it's staying in the open loop mode. I'm stumped too - just throwing out ideas. That "Trac Off" and tach thing is curious too. I haven't heard of any tach failure causes. The "Trac Off" failures are usually a wheel speed sensor which is off the BCM not the ECU. --- It seems like it might be a flaky ECU but I'm just guessing.

5 out of 5 people think this is helpful.
Clayton O'Connor
405

Have you checked the fuel pressure? Could be ECU as mentioned above or possibly dirty injectors or fuel pump. Testing the pressure would rule out fuel related issues

2 out of 2 people think this is helpful.
jsc9306
225

We've tested the fuel pressure and the regulator. Last night we cleaned the MAF sensor, and it was doing better- starting good, no problem. My ex husband's computer said it was a bad MAP sensor. So we replaced that and cleared the codes. It was doing good. I went to the gas station, to get a coffee- came out and it started doing the "no start" again. I drove over to work (across the street) shut it off, and restarted with no problem. It sounds like I am crazy, but I am wondering if there is some kind of "field" in the area of a gas station- because that's where it always seem to give me problems.

10 out of 10 people think this is helpful.
John Saffrahn
29,665

Track off light WILL come on for a bad throttle position sensor. It will also cause it to shift very hard and at high rpms (like you're giving it a lot of gas) any codes in the system? I have first hand seen a throttle position sensor turn on the track off light, check engine light, and make the car shift like it has a B&M shift kit in it.

3 out of 3 people think this is helpful.
jsc9306
225

John, I think the next option is gonna be the TPS... ugh, more money. That trac thing drives me crazy, it doesn't happen all the time though- actually I think it hasn't been happening as much lately.

5 out of 5 people think this is helpful.
John Saffrahn
29,665

Check engine light on? Does it shift hard? TPS is pretty inexpensive and quite simple to change. Also forgot to mention that when it was on, the car was using a ton of gas. MPG went from 23 to 15. If you are seeing none of these symptoms then don't throw money at it.

1 out of 1 people think this is helpful.
jsc9306
225

The check engine light isn't working- possibly burned out...lol When I put the code scanner on it, it will pull codes. I need to check again since the last time- to see what's popped up. The car has been getting better since then about starting. I haven't seen the Trac issue lately either.

2 out of 2 people think this is helpful.
Jason Zane
6,065

do you have a fuel filter in the fuel line? if so.. replace it.

1 out of 1 people think this is helpful.
jsc9306
225

It did have a inline fuel filter that had been changed. As of 2/8/13, I traded the car in. Problem solved. I hated to see it go, but it was getting too old for me to keep putting money into. :(

shelliebobbins
100

i have a 03 malibu 3800 v6 u start it runs/idles till the temp gets to around 170 or so then stalls wait 10 to 15 mins it runs for like maybe 5 mins also check eng lts on and the service tract lt is on any one possibly know what it may be

10 out of 10 people think this is helpful.
John Saffrahn
29,665

Go get the codes scanned, AutoZone does it for free

4 out of 4 people think this is helpful.
wildbill70
170

I have 98 Camry with the same problem... If you pay close attention you will notice that when you make a short stop say 5 minutes that is when you have restart problems . As long as you hold idle for a few minutes with gas pedal everythings OK. I am almost certain a temp part is the problem. If my car sits 30 minutes or more never a problem. Any one witn addl thoughts. Please jump in.

13 out of 13 people think this is helpful.
John Saffrahn
29,665

When was your last tune up? Could be your plugs are worn and the gas that would normally not effect them are effecting then since they are worn.

wildbill70
170

New plugs and fuel filter installed recently. By the way have had this problen for about 2 years.

4 out of 4 people think this is helpful.
John Saffrahn
29,665

Pull the vacuum line off the fuel pressure regulator.

17 out of 17 people think this is helpful.
William Lix
100

When your car starts fine cold, then fails to restart while warm, it is usually a coolant system problem. Either low coolant, or bad coolant level sensor.

10 out of 10 people think this is helpful.
Michael Hargrove
120

Hello my name is Mike I have a 2004 Pontiac grand prix gt right now I'm trying to start it and it wont turn on I'm doing the ignition system reset on it right now but having no luck I've checked the fule pump and it works fine but still not picking up I don't understand what is going on with the car I've also checked all the fuses I'm stumped

12 out of 12 people think this is helpful.
John Saffrahn
29,665

What's your fuel pressure, are your injectors pulsing, do you have spark?

2 out of 2 people think this is helpful.
Margaret Brown
120

My Mazda MPV LX (2000) is doing the same thing. Starts most of the time, then after a few days or a week, after a short stop, it won't start. Alternator was changed 6 months ago. New battery after the first non- start, new Neutral Safety Switch, too. Still didn't help. Very frustrating. I appreciate the tips offered here, and will check them out for my vehicle, too.

10 out of 10 people think this is helpful.
vortech98
110

I just worked on a 05 Pontiac Grand Prix. His car starts fine in the morning. He would drive into work and sure enough it won't start. First I replace the Cam sensor. Then we were still was having issues starting it once the car was warmed up. After further review. I found the Crank Sensors was not working when the car was hot. Yep that did the trick. Car starts when cold and hot now. I hope this will help someone else who may be experiencing the same problems.

11 out of 11 people think this is helpful.
John Saffrahn
29,665

That's where the spark comes in, no spark in any of the cylinders you are looking at either a crank sensor or icm which can be tested at AutoZone.

1 out of 1 people think this is helpful.
4ronharris
150

I have an older Buick LeSabre that is exhibiting some of the same symptoms descibed here. Starts in the Am, a bit rough, but it starts. When its hot, it acts flooded. You have to hold the accelerator to the floor and when it fires, you tromp it real fast and it finally fires and stumbles and then clears and runs ok until you turn it off. I have cleaned the mass air flow sensor, and am now going to test the Fuel Pressure Regulator then I also saw that the connections on the Crank Shaft position sensor can get corroded and cause symptoms of complete failure. So, perhaps we should all check all of the connector pins on all the sensors... ie: The mass air The Throttle Position Sensor The Crank Shaft Position Senor The Injector Connectors The Air Idle Sensor on the throttle body and let me also mention the connections on the ICM behind the glove box and the PROM blue chip as few people talk about that and if it goes the ICM looses its brains. Happy hunting

1 out of 1 people think this is helpful.
Margaret Brown
120

By the way, mine ended up being the starter. My ignition still occasionally gets hot, so they say I may have to eventually have that changed, too, but so far so good.

2 out of 2 people think this is helpful.
skywalka
80

Hi I have a two thousand grand prix that i bought about six months ago. As soon as i bought it i noticed the MPG drop from twenty three to now fifteen and is steady there. Also just recently it has been starting in the mornings, but then not starting if I leave it and come back within about twenty minutes. I've also noticed it shifting hard. Do you guys know what it might be? And also I replaced the power steering pump and now about a month later its started making that noise again. It may be a new noise but it sounds just like the power steering pump. Any ideas about any of these?

5 out of 5 people think this is helpful.
skywalka
80

Oh and the rpms bounce up and down when idling, and bounce even more when I am accelerating and then let off the gas.

2 out of 2 people think this is helpful.
4ronharris
150

I had similar problems and symptoms with my 1993 buick Lesabre, It will start in the am and not after getting hot unless I floor it and tromp it fast. Then it stutters and barely starts and runs ok. Here is the answer: It was a gas tank leak at the seam! Imagine that! Why would that cause such a problem? The answer is modern fuel injected systems have a certain amount of pressure built up in the tank and in the overall fuel rails. So, even though the fuel pump is pumping, it is not pumping hard enough to get up to pressure it needs to start easily. Once running there is more vac from the engine and fuel pressures regular suction and its enough to run....but not really enough during start up.

5 out of 5 people think this is helpful.
4ronharris
150

I did clean up all the senor connectors, but in the end mine was the gas tank leak which lead to loss of pressure. Seal All worked to fix a pin hole leak in the seam of the tank temporarily. $5.15

2 out of 2 people think this is helpful.
skywalka
80

Which of the problems did you're car have as well? Im hoping this could knock off a few of my cars problems

4ronharris
150

It was starting good in the morning and then hardly starting at all when hot. When it did finally start it would sputter and spit and you had to either floor it until it hit, and then really tromp it fast to get it past the stumbling.... It sounded like a timing belt was gone it was so bad......but, after it was all said and done it was a leak in the seam of the gas tank. Seal All, a $5.00 product fixed it for a day or so, and it started right up perfect. Then it stumbled again, so, I am sure I did not get it sealed up good enough on the seam.

3 out of 3 people think this is helpful.
4ronharris
150

Does anyone know if Roof Tar would seal up a gas tank? That stuff is thick and rubberized and may work? But, it may not due to its chemical makeup being that of petroleum.

2 out of 2 people think this is helpful.
longone
60

I had a similar problem, would intermittently not start when warm. it stalled once at a stop light and would only start after cycling the key several times and 1/4 throttle. I tested the fuel pressure, all was normal. I replaced the temp sensor, fuel filter, fuel pump, spark plugs etc. The problem turned out to be a crank position sensor. I didnt want to believe it. I replaced it and the problem is gone. I hope this post help someone out. I wish I knew this $300 ago...

4 out of 4 people think this is helpful.
longone
60

Oh, I forgot to mention that a classic sign that the crank sensor is faulty is an erratic Tachometer reading. The crank sensor drives the tach.

2 out of 2 people think this is helpful.
Jeremy Ballard
20

4 gauge wire from the negative terminal on the battery to your transmission mount will solve the problem.

2 out of 2 people think this is helpful.
Steven Wilson
40

My name is steve i have a 2000 grand prix gtp 188K miles on it. My car starts and runs fine when cold but when warm idles weird and when you shut the car off and go to restart it stalls out. Ive replace MAF, IAC, cleaned throttle body, replace crank position sensor and everything and the only code it has is o2 sensor

4 out of 4 people think this is helpful.
vortech98
110

Replace the cam sensor that is located behide the main crank pully. That's what fix my problem.

John Saffrahn
29,665

Cam sensor isn't behind the harmonic balancer pulley, your referring to the crank sensor.

1 out of 1 people think this is helpful.
Retired_Mechanic
10

After reading most of the post above it seemed like my problem was the crank sensor or trottle position sensor. WRONG. When I first checked my fuel pressure regulator I saw no fuel when unplugging the vacuum line. So I double checked it by doing this, while running I unplugged it and plugged it back about 4 or 5 times. The last time fuel squirted out of the sensor. It must have been a small rip in the diaphram causing the problem I thought?! But that was one problem of 2! My other problem was the Coolant Level Sensor in the radiator! It was bad causing the Track Off light to come one and also the hard to start after warm up problem. After replacing the fuel pressure regulator and the coolant level sensor (Not the Coolant Temp Sensor! NOT) and clearing the codes in the ECM (computer) all is A OK now. Boy that sure was a hard one to figure out even with a code scan tool! Thanks for the information on this forum! 1998 Grand Prix 3.1 V6 was my car.

1 out of 1 people think this is helpful.
Niki Bailey
0

I have a. Grand prix 1998 it cranks up find but when i hit th gas it wont move. Can any one give me a clue y

4ronharris
150

Hello Niki, It sounds like a fuel pressure issue like I was having. If you do some searching on Youtube on there are a lot of videos out there about the fuel pressure issue on fuel injected vehicles. There is a valve, almost like a tire style up toward the firewall side of the vehicle and on top near the injectors. It is possible to attach a free rented gauge from AutoZone to test it.. Now comes the hard part. How do you improve the pressure if it is too low? The typical options are: A) Fuel Pump Replacement B)Fuel Regulator Replacement C) Clogged Injector cleanouts. Last but not least, like mine if you have a physical hole in the gas tank or along the seam of the tank, it can cause the pressurized tank to not build up enough pressure to run the modern day fuel injected systems. So, you either go to AutoZone and buy the fuel tank glue for a temp fix or a junk yard and get a used tank or pay through the nose for a new one. If I had it to do all over I would get a mechanic to do the pressure testing sooner rather than later. They have ways of pumping air into the gas tank and adding dye so that if there is a leak the red dye comes out in a visible gas form. If budget will not allow you to hire a mechanic, then find a friend who is willing to change the gas tank, fuel pump, and possibly the fuel pressure regulator on the fuel rail. The videos on line will help you with each potential job.

ejparsons
0

I have a 1979 Pontiac Grand Prix SJ as long as I'm giving it gas it runs but as soon as I let off the gas it dies and it runs rough I've changed the plugs plug wires thinking it could be that but that didn't help do you have any suggestions

4ronharris
150

I would buy some mass air flow sensor spray and use that on the small wire that is the sensor. It used to be that carburetors controlled fuel mixture ratios, now its all done by computers and they get their information from the mass air flow sensor. There is also a throttle position sensor and it needs cleaning every now and then or replacement. Those two would be my first suspects. If you do a search on You-tube for those two topics you will get enough clues to clean yours. Just do not use regular carb cleaner as it can wreck the mass air flow sensor. They make a very specific spray you can buy at Autozone or some other parts store called Mass Air Flow Sensor Spray. Never leave home without some of it in your trunk as your modern day cars can act up any time and you might save being towed if you just have the cleaner handy. Removing it can be a pain at times. It is a black square 1.5 inch by 1.5 inch chip on the throttle body on most gm cars. It has 4 small phillips screws that hold it in place. You unplug it first then push down on the screwdriver really hard while you try to turn the screws out to avoid striping them out. The heat sort of welds them in at times and they can be hard to get out. So, be careful and be patient. Use the right size of phillips head to give you the best grip.

1 out of 1 people think this is helpful.
Brandon Gelissen
50

Hello I have a 2000 pontiac grand prix I've been having a problem with it for a while now it will crank over but will die shortly after if I keep the rpms over 3000 it will stay running as soon as it drops under that it will die I have replaced the fuel pump, spark plugs, crank shaft sensor, and the harmonic balancer. Still having the problem after that I thought about the ignition lock cylinder and still no improvement I'm running out of ideas as to why this problem keeps occurring any idea what it could be?

5 out of 5 people think this is helpful.
NatalieGold
20

My Sebring 06 convertible with 6 cylinders has had the same problem for about a year now. I took the car to three different mechanics including the Chrysler dealer. The dealer and a second mechanic each kept the car a week at a time and drove it but no one could figure it out. The car starts right up when it is cold. It starts fine after it sits and cools about half an hour after it is being driven for at least 20 miles or half hour. However about 10 to 20 minutes after shutting it off it sometimes has a hard time restarting and running. It does not do this consistently, but when it does it keeps stalling. I can usually get it going by flooring the gas pedal, and if I can get it going, it runs okay after a rough start. Sometimes I can't get it going, and I have to wait around 30 or so minutes to get going again. It feels like it is not getting gas. This only happens restarting the car after a short break (10-20 minutes) after the car is being driven at least 30 40 minutes or on the highway for at least 20 miles. In the last six months, I got a new battery, new alternator, a new hose for a leaky coolent. After I replaced the alternator, it didn't do it for about three months. Recently it started happening more and more often. The engine light came on again today. It's always the same... PO 300 multiple cylinder misfire... Mechanics say that this does not give them much information. It never did it under the watch of a mechanic.. I would appreciate any insight or ideas... Nadine

1 out of 1 people think this is helpful.
Lynn Taylor
0

I'm having the same problem with my 2005 Sebring Convertible. Wait exactly 30 minutes, and it will start and run fine. Almost acts like some theft deterrent circuit timing out, after a false problem detection. Sebring uses a key with a chip in it.

NatalieGold
20

It only does this when I drive more than 10 miles. It starts but stalls and does not go. Sometimes check engine comes up and it is always the same, "multiple engine misfire" I've taken it to a mechanic again. They out new spark plugs but it wasn't fixed. The horn also started going off at random times sounding like an alarm. They had to disconnect it and add another horn on the dashboard. Never another Chrysler again! This will be my last! Since then the

1 out of 1 people think this is helpful.
Bill Klein
0

1998 E150 V6 hard start when warm, I replaced DPFE sensor replaced plugs, coil wires and today the gas pressure regulator that seems to have fixed it, old regulator didn't have a gas smell must of been sticking

Your Answer

Add photo

Related Questions

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 4,246 nationwide Grand Prix listings starting at $1,390.

ZIP:

Search Pontiac Grand Prix Questions

Pontiac Grand Prix Experts

#1 Js08016
Js08016
Reputation 3,510
#2 Tom Demyan
Tom Demyan
Reputation 2,370
#3 munron
munron
Reputation 1,800
View All

Related Models For Sale

Used Chevrolet Impala"
886 Great Deals out of 31,573 listings starting at $495
Used Pontiac Bonneville"
5 Great Deals out of 798 listings starting at $1,400
Used Pontiac Grand Am"
1,981 listings starting at $2,500
Used Chevrolet Monte Carlo"
20 Great Deals out of 2,000 listings starting at $1,995
Used Ford Mustang"
675 Great Deals out of 41,120 listings starting at $1,500
Used Chevrolet Camaro"
553 Great Deals out of 35,663 listings starting at $3,497
Used Chevrolet Malibu"
934 Great Deals out of 61,783 listings starting at $695
Used Nissan Maxima"
331 Great Deals out of 23,030 listings starting at $1,500
Used Jeep Grand Cherokee"
1,135 Great Deals out of 73,078 listings starting at $495
Used Nissan Altima"
1,363 Great Deals out of 85,212 listings starting at $1,599

Used Cars For Sale

2008 Pontiac Grand Prix For Sale
19 Great Deals out of 546 listings starting at $1,390
2007 Pontiac Grand Prix For Sale
17 Great Deals out of 598 listings starting at $2,495
2006 Pontiac Grand Prix For Sale
7 Great Deals out of 733 listings starting at $1,900
2005 Pontiac Grand Prix For Sale
4 Great Deals out of 478 listings starting at $2,300