Just purchased an old chevy pick up with a '92 Corvette LT motor. It runs very well, but when idling, it makes this load "sucking" sound-almost as if it were starving for air. The air cleaner does not look very dirty, and the problem seems to go away when the engine gets hot. Any ideas?

 

It's probably the IDLE AIR CONTROL (IAC) VALVE. The computer commands more air and fuel when the engine is cold so the injectors add more fuel and opens the IAC to give it more air. Someone with more experience with LT engines should be able to confirm this.

 

is it a stock....or BBK throttle body?

 

if using a bellows, check the underside of the throttle body to see if it is buckled creating a gap for air to enter.