[SoCal LS-L]

A good way to check for vacuum leaks is to use about a 2 foot length of 1/2 or 5/8 inch hose and put one end to your ear and the other use to probe around your vacuum lines. If you hear a loud constant hiss, bullseye. Id also try driving a long distance at freeway speeds to burn out combustion deposits (if you do mostly local driving), and dont forget to run the fuel injector cleaner thru. Dirty injectors can cause too much unburnt fuel since they squirt instead of spray, causing incomplete combustion, or something is causing the computer to enrich the mixture too much, such as a vacuum leak or sensor malfunction. No check engine light on?