nopistonsPWR

the car wont rev past 3k after been warmed up... possibly the 6 port....? vacum? car is na s5 89 gtu

fc3s91

iTrader: (23)

Check to see if you narrow range tps is stuck closed.
Thanks Robert

InsomniacFC

iTrader: (4)

Possible clogged cats. Mine wouldn't rev past 4k. Got new cats = problem solved. Also, you could gut them depending on your state smog standards. Since you have an S5 you shouldn't have any issues.

13bSpoolin

have you checked your fuel pump

freemanrx7

Your car is in limp mode.

MY 88 did that -- Turns out it was a bad or stuck AFm

I know your model is diffrent-- So disconnecting the battery may reset the computer.

When you say warmed up do you mean it will rev when its cold?
If so then I would check things that move or change once the engine gets hot.

Jpk3200

Is your check engine light coming on? Check for error codes. It does sound kind of like limp mode.