Problem Description and Possible Solution
The engine may develop a misfire due to worn valve seats. This fault will cause the Check Engine Light to illuminate. Replacement of the cylinder head may be required to correct this concern.
Problem DataRepairPal Verified
Average mileage: 75,333 (65,000–82,000)
Engines affected: 4.2L 6 Cylinder, 5.3L V8
8 people reported this problem
the engine was miss firing pretty bad.i brought the rainier to the dealership. they confirmed the valve seats in cylinders 4 and 6 were worn and the head needed to be replaced at a cost of $3,200.00. the cost over run was so great the final cost was $5,800.00. oh, by the way when a mechanic snaps off the 2 rear head bolts trying to remove them you will pay dearly
Had to have the head replaced, very expensive. GM did cover the parts however, it still cost me 1700.00.