Cool, cause my car hasn't been running so well and i was told to check for vac leaks. Now i know for sure it's the exhaust leak from the slip fit joint in my LT headers.
The only thing u need is a vacum gauge. I work in the parts dept. at a car dealer so i borrowed one from one of the guys in the shop. There is a black rubber vac line going to the back of the intake plenum aka intake elbow or the thingy with the horsey on it. It's the only line going there so u can't miss it. Follow it back towards the passenger side corner of the engine compartment and u'll see there is a split in the line with a plastic connector. Thats where i pluged in a plastic T-fitting and then pluged the line from the gauge to that and thats pretty much it. Just fire up the car let the idle settle and see what the gauge reads.