resently when my car has been running for a little while and i am coasting down a road the reving up and down about 400 rpms up and down. also the oil pressure has slowly decreased since i started driveing. i was told it might be a vaccum leak. does anyone know anything about this?

 

i Had the same probelm with mine (the reving of the rpms) i changed my IAC (idle air control valve) n it stop doing it..its located on the bottom part or your throttle body if u have an lt1

 

I agree take a look at your iac either clean it or replace it totaly. Just if you replace it make sure you get a new gasket for it.

 

thanks ill give it try

 

I had a similar thing happen and it was the TPS.