Hey everyone, I have a 1990 RS and I just got it back from the shop two days ago. It was in the shop for some routine maintenance because I didn't want to break anything trying to do it myself . But anyway, before it went in, I was not able to peel out or go fast at all from a stop. The first day and second day back from the shop I could peel out and get some speed from a stop... Now the car won't peel out anymore! It seems like it still can move good from a stop but no peel outs! I'm not sure but I think maybe it might have something to do with the fuel pump or something like that... anyway, any help would be appreciated.

 

I'm thinking oxygen sensor...

The shop would have disconnected the battery while they were working on it, which would have cleared out the ECM's learned fueling adjustments.

You jumped in, the ECM was running at default fueling, and it ran great.

Then, as the ECM trimmed fueling based on oxygen sensor feedback, performance fell off.

Disconnect the battery for a few minutes, then reconnect it and take a spin to see if performance changed. If so, change the oxygen sensor and see what happens next.

 

It would be helpful to know what exactly they worked on.