I have an 89 camaro Rs, It has always been a bit shakey and when I accelerate it seems to take a bit more gas to speed than usual, however, I took it to the shop to replace the brake vacuum (a different issue) and when they finished the car drove as if brand new. When idle it even felt as if the car was off and accelerated easily by barely steping on the gas.

Now, the car seems to have gone back to the way it was, it shakes a little every now and then when i'm idled and when i accelerate it takes a bit more gas than needed. I checked the car for unusual noises and one concern i feel may be in the converter but I am not sure if this could be the issue in general. Some people told me it could be running low on transmition fluid so i took care of that, had my injectors cleaned and it seems to be a bit better but not "perfect" as to the way it had come out of the shop that one time. I understand that it's 22 year old car but something was done that made it drive like a new vehicle for a few weeks. What could be the problem here?

 

is it thowing any codes??? not an expert by no means and im sure someone will chime in to help more....sounds like the car resetted (maybe if they disconnected battery???), it drove fine, and now its going back to recognizing the original problem

 

i bought my camaro with a blown motor, i had a similar problem. i replaced my 85's original 2.8 with an 89 2.8. the oil pans were different, the pan SAT ON THE CROSSMEMBER haha. i hacked it, shaved it and welded it back on, made it perty again. no more shake, but when i tapped the gas it made all the moving parts center again. one of two problems. bad bearings somewhere, or your engine mounts may be on their last legs. thats what i would assume let me know what you find out

 

Did you check all the lines for a possible vacuum leak?

 

that's not how the computers work. You can clear codes by disconnecting the battery but it doesn't fix the problem, the code just gets cleared.

to the OP, it's a 23 year old car and chances are one of your many old rubber vacuum lines has a leak. 1 can of starter fluid from Wal Mart, have engine running and spray starter fluid around the intake manifold and then around the hoses. if you hear the idle increase you found your leak

Honestly, go to the local parts store and get a bunch of different size vacuum hose as well as heater hose. You'll spend around a whopping $20 and you may as well get to replacing all of them so you don't have to re-visit it again for 20 more years