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.
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.