Have a 1996 gmc 1500 suburban 5.7 350 engine. When the truck hits 65mph there is a slight backfire and the engine statrs to buck a little. Have given truck full tune-up. When it rains problem is even worse until engine warms up. Any solutions? Even my mechanic is stumped at this point. Also have two codes 420 and 300. Cant get rid of
have the same problem?
Wednesday, June 15th, 2011 AT 10:50 PM