Gottabfast

When you put the wider tires on it it may have shifted the subframe back. Put a breaker bar on the subframe bolts to the body and make sure the front and rear subframes are tight! If either subframe shifts it will affect total toe and cause a shifty/wandering feeling.

An unfortunate alignment shop error is to align the front end first. If the front end is aligned first on a Hunter rack it dumps a bunch of toe on the right or left rear corner. Don't ask me why, hunter just tells us to set rear toe before front toe always.

The wider tires probably fixed your car by giving it more grip, which may point to an alignment that's right on the edge. Alignments without driver weight or done when the cars is light may create that condition as well. This problem wouldn't happen to get better or worse when you fill up with gas or have something heavy in your trunk by chance?

iamxpl

his tires are def not too wide for the rim. ap2 rears can handle 255's easy. i believe the OP is running on 235. but since you found that ripped boot, you should def address that.

Gottabfast

Sorry, I wasn't saying the tires are too wide for the rim. I meant that higher load through the suspension/subframe from the wider tires (255s he tested versus 235s normally on the car) may have shifted the subframe back (kinda depends on how they drove it, but still a possibility).

TonysMI4

PLEASE FOR THE LOVE OF GOD.... FIND OUT WHAT IT IS SO I CAN FIX MINE TOO!.

I'v been going crazy with mine having the same crap going on.

2007 AP2 with 61,000 miles.

Tires - Bridgestone Potenza RE760


1.65mph and up I get a vibration from the rear. Seems like its from the pass side but not sure.
2. car feels swirly of sorts.
3. I can make the vibration get better and worse just by applying a small amount of pressure to the gas pedal "o%-3% pedal"
4. I can let go of the steering wheel and make the car pull one way or the other VERY BAD by just pressing on the gas pedal VERY LITTLE.


What I have done to try and fix it.

1.Checked, checked and rechecked the tire pressure in ALL tires. ALL is fine.
2.Installed Innovative Diff mounts. (SEEMS TO MAKE IT WORSE).
3.Installed new wheel bearings in the rear.
4.Have had 2 different shops do an alignment on it.
5.Brand New tires all around "Bridgestone Potenza RE760"
6.checked all bolts in the rear and front.
7.Did the CV axel cup change.


IM LOST!! I'm at the point when I drive I hope someone totals out my car!

ZDan

Have you tried swapping the rear tires left/right and seeing if that changes the direction of the pull? If it does, one of your rear tires is bad. I'm thinking it would be the one on the same side as the direction of the pull when you let off the gas.

TonysMI4

I going to do that in a few days. Its not my DD and I wont have time for a few days. Ill try it but not sure thats going to be it but lets hope

Mr. Orange

Well I just changed my front calipers, as well as all the rotors and pads. The car does feel a lot better, but I think it is in a different way. The car still vibrates a lot. I can say about 65-70 mph and then 75-80mph are the worst speeds for vibrations. Also it still feels really weird. Like the back is being pushed when my wheel is slightly off center, which is all the time because my steering wheel feels like its being pushed around. I couldn't check the subframe alignment when doing the brakes because I couldn't find them and we were in a rush because people were waiting to use the jackstands I was borrowing. The car feels mostly ok in the corners, but at high speeds it just feels like shit.

I'm gonna go get the balance checked again. I tried to check my tire pressure but all of the gas stations were either out of service in the air machines, or they had some weird dumbed down air pump that wouldn't tell me any actual info except that my tires were 'filled up'. (Seriously, wtf).

My brother suggested that maybe I have cupped or abnormally worn tires. I'm hesitant to replace the tires on this car because they might not even be the problem. Other than getting a new balance, alignment, and tire pressure checked by someone with a working gauge, what are my options?

Sounds like we have similar issues. If you solve your woes be sure to let me know what's up, and I'll return the favor if I do.

Gottabfast

High speed instability sounds like toe issues. Either 1 rear wheel or your total toe between front and rear. Subframe bolts to body being tight is first thing to check, if they're moving/shifting you're going to be chasing your tail with everything else. Once you confirm those, try another alignment check with tire pressures set.

High speed vibration...steering wheel? Pedals? Floor? Seat? Depending on where you feel the vibration, it could be tires, diff, driveshaft or propshaft. Usually driveshaft is lower speeds, but it can also have an odd 3rd order vibration that occurs at higher speeds as a buzz. Has the vibration been there all along or did that start at a different time than the instability?

arsenal

It would defintely help if you posted some pictures of the tires you currently have in their current state...

iamxpl

have you changed your diff oil recently?