03 WRX sedan 4 EAT (135k) tuned by JM years ago...runs fantastic. Suspension mods consist of four-way adjustable KYB AGX on Prodrive springs, poly steering rack bushings, and front/rear STB. Brakes (Stoptechs) work straight and firm with no pull bias and car is currently running on stock size (205/55/16) blizzaks or arctic alpins (can't recall). The issue over the past month is the car will wander when ever so slightly loaded (weight transfer) on the passenger side and has to carefully, yet immediately be corrected. It requires some serious concentration. PS fluid at an appropriate level and was replace when rack was replaced ~4-5 years ago. I am going to have it up on a lift this Saturday. Likely Culprit? Where/how to begin diagnosing? Thank you -Rick
First thing to check when a car pulls, is tire pressures. Although that tends to be a dull, constant pull to one side, I wouldn't describe it as "requiring concentration". Look for play in all the moving suspension parts. Ball joints would be high on the list, but inspect all the suspension bushings and such. My Celica had a rear inner lateral link bolt work loose (I had taken them apart years ago for poly bushings) last summer that caused all kinds of odd characteristics. Even a wheel bearing can cause symptoms like that (almost always accompanied by a noise, so not likely, but worth checking). Also, with the front tires on the ground, have somebody turn the steering wheel side to side, and see if your steering rack moves.
If you are willing to spend a little time/money/energy bring the car over to Jeff. He can get it on the alignment rack and not only check alignment but all the components being suggested above. He can take a fair amount of energy to deal with but he knows his stuff and will be able to sort it out for you.
Bad tire (broken belt)? Does it happen everywhere you drive it? Maybe it is a road irregularity on the road you usually drive on.
I don't think that's the case. It does more on left-hand curves than right. Think about the crown in the center of the road. On roads where it's minimal, fewer issues. Otherwise, it's white knuckle driving just waiting for that pull to happen than quickly recovering without overcompensating.
I won an extra trip back to Rich's in 2008 when I had a front bearing detonate at the ice races... The Camber on this front wheel was all bearing play: https://carl-s.smugmug.com/Vehicles/Car-events/Mnsubaru/Mnsubaru-ice-race-edited/i-b9fgpvx/A
