Horrible Idle
 

i just had my engine rebuilt on my 97 cobra. while it was out did many mods such as lt headers, performance valve job, underdrive pullies, centerforce dual friction clutch, and jlt cold air intake. the car was put back together and idles HIGH! up to 4,500 rpm. it goes up and down annd car even dies. the mechanic tells me i need a high performance idle air sensor? also says a new mass air flow sensor is necessary for my intake. also my clutch makes a grinding kinda sound when i push the clutch down when in motion. he tells me its probably just being broken in. let me know what you guys think.

he's high...

the idle issues are a serious issue. that's usually a sign of a vacuum leak or a stuck IAC. In any case, do all the usual protocols for finding a vacuum leak, check for any codes and make sure to clean the MAF and IAC valve.

The clutch is mal-adjusted.

+1, he's full of $hit, find another mechanic...

prob. fixed, said the throttle body was full of carbon.. only one problem, engine is knocking AGAIN, 5400 dollars later!!! thats why i had it rebuilt in the 1st place. whats a brother to do?

Take it back to who built it.

+1. Did you get a warranty on the engine rebuild? Either way, sounds like the shop that did the work hasn't finished the job yet.

he claims he does, how well, we'll see tomorrow morning when i give him a call.