I bought my 1994 Firebird used about a year and half ago and haven't had any major problems with it at all. I love the car but lately (I'd say within the past few months, actually) it's been acting weird.
Up around certain speeds (between say 55 & 70 mph) the steering wheel will sometimes "shake" or "wobble" from left to right... once I get up around 80 it quits and down below 55 the same thing. Not really sure what is causing this. It wasn't doing that when I bought the car and like I said only recently developed.
More recently, within the last month, it has been running smooth, no shakey steering wheel, but when I get above 60 mph and then come back down in speed (whether via hard braking or coasting) my Service Engine Light comes on as soon as the speedo hits 60. All of my gauges are fine, oil, temp, all of that is tip-top, and like I said it actually is running smooth. The SEL stays on until I turn the car off then back on and then goes away. These 2 scenarios seem to appear at random. One day I'll get intot he car and it'll be shakey steering wheel but no SEL, the next day it'll be smooth but SEL will come on as described above. Now, I'm certainly not a mechanic by any means but I just can't seem to figure out why this is happening.
In an effort to try to figure this out I went to Pep Boys and bought one of those cheap Actron code readers for my car. It is supposed to make the SEL flash when you plug it in to that slot (forget what it's called) and turn your car to standby mode (battery on but engine not running). However, the SEL doesn't flash, it just stays on. I refered to the Actron manual. It said refer to my servicing book. I looked in my Chilton guide and it said that if the SEL stays on during a code read that I might have to have a "drivability technician" look at it. I have no idea what that is but it sounds scary. :>
I really just want to figure this out. My engine should be (and as far as I can tell is) running fine. Coolant, oil, transmission fluid (including dropping the pan) and all that good stuff is changed regularly by my father and me. My father has been a diesel and car mechanic for 20 years and can't figure it out. I know that my shocks are shot and I need to get new ones, but could that cause my SEL to come on?
Anyway, any help would be great... sorry for the long post.