i recently installed new valve cover. Put everything back together and now the car runs and idles rough. There is no apparent fuel or oil leaks. I have tried to check all hose to make sure im not leaking air. But the car doesnt want to rev past 2.5k and backfires from time to time. Can anyone assist me please.

 

First make sure that you tightened everything up to specs, A vacuum leak will cause rough idle.

If you cannot rev past 2.5K, Then your car may be in limp mode, Are you getting any CEl?

Check you haven't switch around the coil pack connectors or you will be getting a misfire.

Also, You will have high idle If you removed the throttle body without disconnecting the battery, In this case, You will need to do the reset:

http://www.technosquareinc.com/350reset.htm

 

yes i checked everything. i think i may have switch the connectors. I took the battery cable off and reconnected it and it reved past 2.5. While driving it just has slugglish accelaration. It more or less sounds like a subaru.

 

I'm having the same issue now...did head gaskets, car runs fine but when I rev it up, it misfires and white smoke out the exhaust...it sucks