Highter Than Nornal Idle Due to Vacuum Leak on GMC 1500 Pickup

An engine vacuum leak may develop from the throttle body gasket causing a higher than normal idle speed. Failed gaskets should be replaced.

RepairPal Verified
Average mileage: 118,900 (17,800–220,000)
Engines affected: 5.0L V8, 5.7L V8, Gasoline
6 model years affected: 1990, 1991, 1992, 1993, more1994, 1995
9 people reported this problem
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problem details
1991 GMC 1500 Pickup - 5.0L V8 220,000 mi,
replaced intake gaskets and TBI gaskets, still has occasional high idle and stalls constantly.