I have a 93 GXE with 128k miles. I just have it tuned up last Thursday. After 2 days, when I finished a 65 mph downhill, it went wrong.

It can not exceed 40 mph while the engine runs at 4k to 5k rpm. If I turned the OverDrive off, it can be accelerated to a higher speed with much higher rpm than normal.

I asked 2 mechanics' opinion. One believed it is a transmission problem (internal problem). The other one thought it might be related to the tune-up. He guessed there is something unplugged in the vacumm line.

Anyone has experience on this? Thanks in advance.

 

this sounds like the problem I had before my second tranny rebuild. the car will only be going 35-50, but the RPMS will be in the 4's-5's and stay there like you were really pushing it fast as hell. Don't mean to scare you but it might be a prob, just keep an eye on it and be prepared for the worst if it doesn't go away.....good luck!