Car will sometimes not start after warm.

jsc9306
95

Asked by jsc9306 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?

30 Answers

tenspeed
55,115

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.

2 out of 2 people think this is helpful.
Clayton O'Connor
275

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

jsc9306
95

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.

3 out of 3 people think this is helpful.
John Saffrahn
16,825

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.

2 out of 2 people think this is helpful.
jsc9306
95

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.

1 out of 1 people think this is helpful.
John Saffrahn
16,825

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.

jsc9306
95

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.

1 out of 1 people think this is helpful.
Jason Zane
3,535

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

jsc9306
95

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
50

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

5 out of 5 people think this is helpful.
John Saffrahn
16,825

Go get the codes scanned, AutoZone does it for free

2 out of 2 people think this is helpful.
wildbill70
50

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.

3 out of 3 people think this is helpful.
John Saffrahn
16,825

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
50

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

2 out of 2 people think this is helpful.
John Saffrahn
16,825

Pull the vacuum line off the fuel pressure regulator.

7 out of 7 people think this is helpful.
William Lix
30

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.

3 out of 3 people think this is helpful.
Shane Hargrove
20

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

2 out of 2 people think this is helpful.
John Saffrahn
16,825

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

Margaret Brown
20

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.

2 out of 2 people think this is helpful.
vortech98
20

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.

2 out of 2 people think this is helpful.
John Saffrahn
16,825

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
0

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

Margaret Brown
20

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.

skywalka
0

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?

skywalka
0

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

4ronharris
0

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.

4ronharris
0

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

skywalka
0

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

4ronharris
0

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.

4ronharris
0

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.

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