02 GP Shakes upon accelerating

**riddell87** · 12-01-2009

Hey, i've got an 02 grand prix gt and have had some problems. Lately when i accelerate the car shakes furiously but can be bypassed by either having a very slow start or hit the gas harder(lol), and is even worse when it comes to getting on the highway or trying to pass. If you just let it keep shaking the engine light comes on and blinks and will sometimes stay on or just turn off. I had it scanned and it came up with several miss fires. I replaced the plugs and ignition coils and it did not solve the problem. There was some other vibrating while driving but replacing a bearing and arm fixed that problem. This feels like its more to do with engine/electrical. Has anyone else had this problem? Any help would be much appreciated, thanks.

**Bio248** · 12-01-2009

its an axle.

**TheOtherNick** · 12-01-2009

Originally Posted by Bio248

its an axle.

axle wont set a miss fire code. Check fuel pressure and injectors. You replaced the wires when you did plugs and coils right.

**cerick08GP** · 12-01-2009

So are you still popping codes? If you are still misfiring I would check the spark plug wires. Also, if you still have your coils keep them. They are probably better than the replacements you got. Or better yet, put them back on and try to return the new coils. Anyway a shaking car tends to be a mechanical thing, but that contradicts the misfires. Change/check the wires and have it scanned and get back to us.

**riddell87** · 12-01-2009

i haven't changed the wires but that'll definitely be the next thing i check out seeing as its an easy one. i have yet to scan it since i put the new coils in(tonight) but when i changed the plugs a week back it still miss fired. I'll check back soon hopefully with the answer to the problem, Thanks!

**corvetteii** · 12-01-2009

if you let off the accelerator while driving, does it stop shaking? If it mainly shakes during acceleration its most likely an axle/cv joint. I just replaced these on a 98 GTP that was shaking upon acceleration and fixed it.

**riddell87** · 12-01-2009

yeah the shaking will stop if i let off the gas. It'll mainly do it if i need to accelerate quickly or trying to accelerate on a incline. whats an axle job like, pricey?

**Bio248** · 12-02-2009

i dont think the misfires have anything to do with the vibration.

**corvetteii** · 12-02-2009

Originally Posted by riddell87

yeah the shaking will stop if i let off the gas. It'll mainly do it if i need to accelerate quickly or trying to accelerate on a incline. whats an axle job like, pricey?

well each axle is around 70 bucks. Then you need to rent a FWD axle puller and a slide hammer from autozone to pop the axles out of the transmission. You get all the money back when you take the tools back. The job is really not that hard.
*jack up the car, take the tire off.
*remove the 33mm (you need a deep well socket) hub nut that holds the axle in the hub.
*remove the two nuts at the bottom of the strut and slide the bolts out.
*then take the axle out of the hub and use the puller to pop out of the transmission.
*be careful when putting the new axle in to not damage the axle output seal.

When its all back together ensure that there are no transmission fluid leaks at the axle seals ( Start car and drive around the driveway or something).

This job will cost at least $300-450 if you take it somewhere or $150 DIY.

**corvetteii** · 12-02-2009

I forgot to mention, this GP that i changed the axles on did set off an engine code due to the vibration. Just disconnect your battery and then turn on your headlights for 10 minutes. The object is to remove any residual voltage from the ECM and it will turn off the code. If the code comes back later, then you know you have a problem.

**riddell87** · 12-02-2009

Thanks corvetteii, i'll check it out.

**riddell87** · 12-19-2009

well fixing that will be put on hold for a bit, got smoked on December 11th by someone who thought it was okay to pull out in the far lane without looking, maybe the shop will fix it thinking it happened in the accident haha

**copgtp** · 12-21-2009

if he is pulling a BLINKING SES light while this vibration happens, I seriously doubt the problem in in suspension. The only thing that will trigger a blinking SES light is a serious misfire in the engine. I understand where everyone is coming from but I doubt axles are your problem. make sure all your wires are going to the right plugs, clean the contacts on each ignition coil, maybe even replace the coils, it's not a bad idea.

**Zef_66** · 12-21-2009

Originally Posted by Bio248

i dont think the misfires have anything to do with the vibration.

Originally Posted by corvetteii

I forgot to mention, this GP that i changed the axles on did set off an engine code due to the vibration.

Wow, lots of interesting advice in this thread. Too bad I just found it now.

First off, the mis-fires are the most likely reason for the vibration. A misfiring engine is not going to run smoothly. It will shake, and rattle and carry on under acceleration. It is not going to run or drive smooth. And the fact that the OP showed a flashing SES light, which means multiple misfires, and even pulled codes to back that up should point directly to the misfires causing the vibration. If they are bad enough to set the SES to blink, they are more than bad enough to cause a vibration like described.

As for the axles setting off an engine code for vibration. I would really like to see this happen and know what code it set off. Because I can't think for the life of me how this can happen.

To the OP, I would like to apologize on behalf of the members in this thread that have led you astray. If/when you get your car back, check the firing order of the plugs and wires to make sure everything is correct. Have the cat checked to make sure it isn't plugged. And check fuel pressure and your injectors on the cylinders that are showing the misfires.

**riddell87** · 01-05-2010

Just got the report back from the collision center and they scanned to see what the problem was cause they felt it when they test drove it and now its reading a cylinder miss fire i forget what one but they said the plugs, coils an wires are fine, and we had replaced the cat a month ago. they didn't fix it cause they went along with it didn't happen in the accident ha. oh well, it was shy of $1000 from getting written off, so close! hopefully cylinder jobs/this one wont get too pricey.

Thanks for all the help.

**copgtp** · 01-07-2010

I would change out the wires and plugs regardless of what the shop says. It is a cheap ticket and is required in regular maintenance anyway! If you still have the problem then just get one new coil pack...swap them out one at a time with the new one until you either find the problem...or nothing is changed. That way you're only out the price of one new coil pack instead of three!

**riddell87** · 01-08-2010

Problem solved! haha, i had changed the plugs and all the coils already and skipped maybe one of the easiest jobs, the wires. One of the wires was pooched and was mucking up everything. Thanks to all who posted, specially the ones who suggested the wires. It's now for sale, check it out or if you know anyone looking for a good deal on a car, drop me an email.
2002 Pontiac Grand Prix GT Sedan - Guelph cars Cars For Sale - Kijiji Guelph

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