compression

don't know too much about mechanic aspect of a car engine... bought a used 91 Chevy z 28 , drives fine. but sometime waiting @ red light , engine idles rough for few seconds and it happens in a few seconds interval. if i turn on the A/C , it idels ok . there is oil leak @ the back top part of the egine . i changed the spark plugs already. and my friend told me it could be compression issue.

Well first, this belongs in another section. This particular thread was posted in the LS1 engine section, the LS1 is a far superior engine to the one you have in your camaro.

All that aside, there are a number of different things i'd check before a compression test for a rough idle. Start with those string like things attached to the spark plugs you changed, and work your way up.

Moving...

Also check your EGR and evap. canister.