[dannym]

Start with the basics. Check for vacuum leaks first, and then exhaust leaks. All must be sealed up. Look for cracked or loose vacuum hoses going to the fuel pressure regulator, MAP sensor, vacuum purge valve for the carbon canister, and the carbon canister itself, probably located in the rear of the car near the side quarter panel. Clean the intake throttle body and IAV valve. Check for intake manifold leaks by spraying carb cleaner around the gasket with the car running, if the engine speeds up, there is a leak. Check my other posts for 1990 Lumina.