Whats wrong with my GP??

2007 grand prix gt

I love my baby (car), and I have been spending a lot on one problem: vibration only while on the accelerator.

Told it was tie rods and wheel bearings (front), with it being a front wheel drive car it was causing vibration because of these bad parts and putting them under pressure when on the pedal.

Okay so I replaced those for a lot of money. Multiple places would love to sell me CV Joints, but i have gotten very reliable answers that they are okay. Before parts were replaced the vibration was severe in the steering wheel and seat, almost making the car undrivable, now it's much more minute in the steering wheel as well as the seat. highway speeds are the Achilles heel.

Picked it up today, and the car feels better, but it is still vibrating under acceleration. Tires are okay, even replaced two as well. All tires are the same (Primewell PZ900). All maintenance is done to the car, aside from alignment. But no tire wear present indicates bad alignment.

Vibration is severe above 3k rpm. It was much more violent before bearings and tie rods were replaced. Car is drivable now, but i want to get this fixed. Would alignment fix this issue? Sounds too good to be true. Also, would a bent rim be giving me this problem? Im just throwing around ideas.

Main thing is, it is seriously only vibrating while under acceleration, any speed. Let off the gas, any speed, and it is smooth as can be. Please help me!

It is worth noting I asked about mounts and they said they are okay. Say Im accelerating over a hill, the vibration is worst going up the hill (while on the gas), and is also bad when i hit the bottom of the hill (i.e., there is a lot of weight on the car). I am no Kurt Busch but I really think its in the wheels somehow.

Thank you so much for your time in reading about this and please let me know if I could provide any additional information that might help zero in on this issue.

To me it sounds like a possible cv axle. since it is while accelerating I would not suspect a rim or tire. The transmission and cv axles can cause a shudder under load. does the car run ok like the idle and stuff of that nature? You feel it in the steering wheel and seat so I would suspect something in the front end or drive train. To see if the engine/trans mounts are an issue you can have someone power brake the car in quick bursts in drive/reverse and look at all 4 mounts for excessive movement. Unfortunately it could be a host of things. keep us updated

Thank you for your help. The car runs great in idle. I even suspected a motor mount so I gave her some gas in park to rev up the engine, no rattle whatsoever.

Its getting worse day by day. Why do I think that balancing the tires and an alignment would help? I really feel it would but I dont want to waste money and no one will do it because they feel the vibration and search my car, drive my car around burning up my gas yet fail to diagnose it.

This situation is becoming very stressful, as I need it for school and work and was forced to take it from the shop to drive from Dallas to Lubbock last night.

I am a college student and have spent all my saved money trying to fix this. I would really appreciate any extra advice!!

Thank you

I have to agree with rickisrad on this. I have replaced several axle shafts on GP's for this very same complaint. Also check the ball joints for wear. Worn ball joints will amplify the problem.

How much would a repair like that cost?

you can get the cv axle for about $60-80 and it is definitely a DIY. A shop will charge you about 1.5 hours labor and jack the price up on the part.

Curious....but could this vibration be due to bad wheel hubs making the traction control be off? I remember my car sort of skipping while under acceleration when I had a bad hub but my anti lock brakes and traction control light were both on at that time.
Zep

Curious....but could this vibration be due to bad wheel hubs making the traction control be off? I remember my car sort of skipping while under acceleration when I had a bad hub but my anti lock brakes and traction control light were both on at that time.
Zep

He replaced the bearings already. I think the traction control situation you are talking about feels more like the ABS kicking in for a moment and usually has the buzzing sound associated with it.

Just to be sure I would also make sure those Primewells are balanced correctly. I would have the balance checked by another place in case the machine (or technician) is not calibrated properly.

I doubt it's a tire balance problem, since the vibration goes away when not accelerating....

Had a car come in with the CV boot torn and grease everwhere....replaced he CV axle......customer came back the next day....says when he is out on the highway, and accelerates, he gets a vibration......road tested it and sure enough, the vibration was there......since the only thing that was changed was the CV axle, it had to be that.....on the lift, felt no unusual movement from the axle.....

Got a replacement one.......installed it, and the vibration on accel was gone....first time that I had ever run into something like that....in my case, it was easy to determine what the problem was, because I had just replaced an axle......since there was no real movement I could feel in the joint, not sure how you would determine which one was causing the problem....thinking back, what I should have done was put the car on the lift and had someone accel and coast the car, and then see if there was movement or noise coming from the axle.....but then again, being off the ground, with no load, maybe it would have shown nothing....

Yeah my ADD kicked in, I said that earlier in the thread about the front end and cv axle. I should have clarified about the balancing and put as a side note Primewells aren't the truest of tires. Aftermarket cv axles are hit or miss. I have had the best luck with NAPA axles, but on customers cars we had to use the cheaper ones for more of a profit margin. I wish someone sold a hd cv axle rebuild kit for our cars for higher horsepower builds.