Engine power loss and sputtering


Asked by PoppaQ Mar 06, 2007 at 11:21 AM about the 1995 Pontiac Grand Prix 2 Dr SE Coupe

Question type: Maintenance & Repair

It seems like I have a loss of power when accelerating and driving around 50-60 mph at ~2k rpm. The car also sputters and rpm begins to fluctuate while driving. Is the fuel injector bad or clogged and how would I clean/replace it? I want to fix this myself but I'm quite the car newbie. Thanks!

37 Answers


Dear PoppaQ-- I could list 25 reasons why your car is sputtering while driving, but let's start with the most simple solutions first. It may be your fuel injectors. Buy some fuel injector cleaner at a parts store. Run a tank of gas with that and see what happens. I would also check my airfilter. If it is clogged or dirty it could be contributing to your trouble. If neither of these work we may have a clogged fuel filter, some spark plugs or spark plug wires in need of replacement or even a bad fuel pump. Start with the easy cures and let me know how you do. Good luck from Bovan.

55 out of 55 people think this is helpful.

I tried filling the tank twice with 93 ultra/premium gas and a bottle of fuel injector cleaner each, it still sputters and loses power when accelerating at first. When the weather clears up I will pop the hood and check the air filter. I think I just replaced it last year...

27 out of 27 people think this is helpful.

I have a 2008 Pontiac Torrent. While traveling home on the freeway at 65mph the engine began to stutter, especially when trying to go up any type of grade. I slowed down to 50mph before the "stutter" went away. I had a similar problem while traveling in Florida. At that time it was determined to be a "blown" spark plug, whatever that means.

52 out of 52 people think this is helpful.

I have a 2003 grand prix and recentl went on a road trip. I got worse than normal fuel mialage so I change my fule filter. It was fine for the drive home but I now get the sputtering when taking off until I get up to higher rpm's. Is it possible that I am sucking in air through the fuel filter connections? Or could changing the filter have caused any other problems with my car such as the air intake sensor (not sure what its actually called.

104 out of 104 people think this is helpful.

My 1999 GTP experienced the sputtering problem at 28,000 miles and it was the result of a defective wiring harness. I assume this to be very unusual but it can be the cause. Best of luck.

15 out of 15 people think this is helpful.

did u have loss of power with the sputtering...because i do big time...i have a 99 gtp 2dr coupe and it has 180000k on it..if im at a dead stop and i punch it the tires wont spin and its sputtering....so many people r trying to tell me bull shit and that i need a new engine...i dont know what 2 do...and it feels like i can only trust a some one with a gtp that went threw the same thing.....

56 out of 56 people think this is helpful.

hey man im going threw the same thing and tried the same things....im lost....did u find out what the problem was...if so let me know what it was..because im lost...people r trying to say i need a new engine...

16 out of 16 people think this is helpful.

My 3.8 Supercharged engine created about the same horsepower that you would expect from a YUGO automobile until the wiring harness was replaced. The same sputtering and shaking that you report. My engine had only 28,000 miles on it at that time and now has 122,518 miles and runs smoothly and produces a bunch of power. I still enjoy owning it.

18 out of 18 people think this is helpful.
Chase Sutherland

are you throwing a CEL? because if your car is running like this im guessing it is. go get it scanned and see what it is.

5 out of 5 people think this is helpful.
Not Active

For all you PONTIAC folks,Google pontiac problems,you will be sent to a Grand Am site,heck im even on their.lots of great info on pontiacs.a lot of guys their really know their stuff about theses cars.

9 out of 9 people think this is helpful.
Bernard Cough II

go to auto zone, they'll throw it on a scan tool for you for free. that should tell you the issue, or at least point you in the right direction. most likely in my opinion? MAF sensor. when that goes, the computer doesn't know how much fuel to put into the engine so it repeatedly switches from too rich, to too lean causing the engine to run like garbage while trying to maintain a steady rpm, and have insufficient power under accelleration.

21 out of 21 people think this is helpful.

my 99 gtp dies out when the temp gets to around 200 but it will idle till its hot as hell but it wont drive. u have to wait for it to go back down below 200. while ur driving feels like its not getting any gas but the lights flash so i think its electical. hooked it to a scanner and it wasnt throwing any codes my first car and already replaced fuel tank pump. tried fuel injector cleaner exaust system.

8 out of 8 people think this is helpful.

Since you have stated on repairing and working on the car by yourself, I can assist you further on this count. I too like tinkering with my cars ( a Seville and an Outback) but did not know the details of car maintenance. I regularly look up these http://www.automotix.net/autorepair/diy/ which are very easy to understand and enable you to perform skillful tasks on the car.

8 out of 8 people think this is helpful.

I have a 1998 gtp and when I first got it there were no problems with it, then the fuel pump went out then the water pump got them both fixed and not too long after that it began bogging and losing a lot of power. I had someone hook it up to a code machine and all the codes said catylatic converter so I had that removed. it helped but the car still boggs and has a bad power loss, it randomly stops bogging and starts running fine but not too long after it stops it starts doing it again..

20 out of 20 people think this is helpful.

i have a similar problem 1998 mustang gt 4.6 with 106,000 miles and it sometimes wont hold an idle and will idle and fluctuate from 1000 to 2000 rpm and sometimes even stall and when im driving it sputters from 1000 to 2000 rpm but when im punched it doesnt and even when i try reving the engine it cuts out for a sec and then revs i changed my spark plugs and cleaned my air filter im going to get injector cleaner tomorrow and open up my throttle body im having a lot of trouble and need help please someone help me out

25 out of 25 people think this is helpful.

i have a 4.6 cougar1994 137000 miles(my Dad`s last car),slight cutting out upon heavy acceleration( accelerating lightly i can ease it up to very high speeds,over 100mph and smooth)i read with interest all the comments HAH,this internet converse is so great man!! i will try the fuel injector cleaner as a first resolution,maybe have someone look at the computer if she doesn`t straighten up,may we all be blessed with a good resolution:-)

3 out of 3 people think this is helpful.

I have an 06 gp base sedan 3.8 v6. @106000 we changed the trans filter ,every 3000 since we owned the car oil was changed.it suptters @30 mph to 70 mph we lost a price from the injector clip ....got a new harness ...never a problem again.

2 out of 2 people think this is helpful.

I have an 06 gp base sedan 3.8 v6. @106000 we changed the trans filter ,every 3000 since we owned the car oil was changed.it suptters @30 mph to 70 mph we lost a price from the injector clip ....got a new harness ...never a problem again.

2 out of 2 people think this is helpful.

I have a 1994 kia sportage which all of the sudden began to loose power while driving on the highway. I took the vehicle to my mechanic who checked various sensors, the wiring and connectors but found nothing wrong. After changing spark plugs, coils and coil wiring, fuel lines and carrying out test to the fuel pump, relays and cleaning earth masses the problem continued. Finally the wiring harness that connects the fuel injectors, the TPS, the canister valve and the EGR was tested and found that the actual connector wires of the TPS were not completing the circuit and needed welding. This was the answer to the problem and the vehicle is now running well. For those of you with a similar problem I suggest you investigate the wiring harness before changing sensors, pumps or other expensive items.

7 out of 7 people think this is helpful.

Same problems with 2000 sunfire replaced all the usual suspects plugs wires,tps,coils,idle sensor turned out to be ignition control module was gone once i replaced the module check engine light went off the car worked fine ever since.

2 out of 2 people think this is helpful.

Depends how long you are traveling daily how often you drive your car..now you got to think use common sense,,same situation happened to my 88 Fiero GT, I am not 100 % sure, but your fuel pump deminis power have it replace or have it pressure check. Normally, fuel injectors hardly get dirty,, sometimes loss or leak vacuum hose is the cause have it self check

1 out of 1 people think this is helpful.

Take bovan advice..losing power has a lot of cause..common sense will help..use W words, like when what why where..This will help when was my last tuned up, what parts did I used, don't use cheap parts they won't last long, this won't help your gas mileage and will cost you more money

Byron Wilmoth

Just to provide my experience. Be sure to check the rubber boot connectors for the vacuum where it connects to fuel pressure regulator and at throttle body and trans. Mine were all cracked and leaking and not obvious. All of the damage was on the bottom out of sight. I moved them and there it was. Replaced them and problem solved. This after wires, plugs, fuel filter, ignition module replaced. A lot of those pieces in the vacuum system are discontinued so you may have to engineer a proper fitting boot connector. Hope this helps. I spent ten dollars to fix it.

6 out of 6 people think this is helpful.

I have the same problem with my 2005 tiburon sputters between 3000 and 4000 rpms. Mechanic cant find anything. I have tried fuel injectors, filters, MAF and nothing worked. The strange thing is that in the cooler Phoenix winter days it is fine but when it gets warmer it starts again. And no it does not matter if the ac is on or off. Do you think it is the wiring harness as Trackless mentioned?

3 out of 3 people think this is helpful.

I had the same problem and I only changed my car battery and the problem was solved.

1 out of 1 people think this is helpful.

99 Pontiac grand prix gtp first the car would randomly die and blow injector fuse so I replaced fuel pump resistor and fixed problem for 2500 miles then blowed injector fuse again so I replaced fuse as soon as I cycled key to on position it would blow fuse after 30 mins or so it didn't blow fuse so drove it home now it will not start and the fuse is good! if I spray starting fluid in throttle body the car starts until it burns off...so obviously I have spark just no fuel?? in last 6 months car has had new maf sensor o2 sensor tps sensor cam and crank sensors any help would be greatly appreciated as me my wife and 4 year old have no family in area and this is only car so HHHEEELLLPP!!! LOL thanks

2 out of 2 people think this is helpful.

TomcatSuperD what wiring harness did you replace?

2 out of 2 people think this is helpful.
Adam Freeland

I have a 1996 mustang GT when the car is in drive I hear a humming sound and the rpm moves up and down then the car trys to shut down I have to put it in park an hit the gas to keep it from shutting down what could be the problem? adamfreeland19@gmail.com

2 out of 2 people think this is helpful.
Adam Freeland

I have a 96 mustang GT when the car is in drive I hear a loud humming sound then my rpm gauge moves then s just a little power lost I found out the humming sound is coming from wher the air filter go I put my hand on it and it was vibration what could be the problem?


Check the intake air flow sensor it might be faulty.


I have a 1999 ford mustang with cold air intake and a performance chip I had some of same issuesi replace coil pack wires and plugs swaprd manifolds for headers with new gaskets replaced intake gaskets put in limited slip diffrential and 8 inch gear I cans topi tan don issues so far


Clean the MAF sensor and throttle body

Stephanie Losiniecki

I have 2001 vw tri beetle. I have replaced my maf and fuel filter but I am still with no power and I sputter really bad in 1st and 2nd gear. Once I'm in the higher gears I just have no power and almost seems like I hit a rev laminator at 2000 rpms what else could this problem be!

1 out of 1 people think this is helpful.

Get your fuel presure tested - Sounds like it could be your fuel pump..

1 out of 1 people think this is helpful.

ok so I have a 2000 camaro V6 and I had a leak in the fuel line coming from the tank, I fixed it and now it acts like its got bad gas or something. It goes for about 5 or six miles then starts spitting and sputtering then dies and has to cool off for a minute before it will crank back up. I've had to be pulled home twice now. Anyone know what it might be? Its not the fuel pump or relays I've already checked those.

2 out of 2 people think this is helpful.

oh and already checked the fuel filter too.


I had an '89 Pontiac Grand Prix and it sputtered and was sputtering and rpms going up and down and losing power; just acting like a clogged fuel filter or injectors or air filter. Once one injector goes bad, the rest usually tend to follow suit so I had them all replaced. Come to find out, it was the coil pack. My friend had same thing happening with her car and her mechanic would not listen to her when I told her to tell him this. But guess what, after replacing fuel filter and spark plugs he finally wanted to replace the computer but she told him she wanted coil pack first. Hard to diagnose because it tricks the scanner into thinking its things it's not. Ends up being pricey. I mean, when the brain of the computer is bad, of course the computer will give scanner false codes.

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