The throttle body gasket may develop a vacuum leak which may result in a higher than normal engine idle. Failed gaskets will require replacement.Google+
Car Problem Reports
Chevrolet 1500 Pickup Idling Problems Due to Vacuum Leak in Throttle Body Gasket
Chevrolet 1500 Pickup Problem
Engines Affected: 4.3L V6, 5.0L V8
Average Mileage: 171,000 mi (148,000 mi - 194,000 mi)
Visitor, 1994 Chevrolet 1500 Pickup, 4.3L V6, 194,000 mi
engine idles too fast, wasting fuel, and making it unsafe at slow speeds, because i have to have my foot on the brake. carb cleaner sprayed at the base of the throttle body, when idling, is sucked through, causing the enging to bog down for a short time. I suspect a gasket failure.
This problem has not been fixed yet.
Visitor, 1991 Chevrolet 1500 Pickup, 5.0L V8, 148,000 mi
higher than normal idle, just started looking for solution.