[IRA51]

Try this, change your fuel filter,check your air filter and replace if dirty,if you have a K&N make sure you do not over oil it ,remove all the spark plugs and get a can od GM top engine cleanrt from your local Chevy dealer and use a funnel and a piece of rubber hose and pour it in all cylinders let it sit over night than spin the engine over a few times to force out the remaining fluid ,replace the plugs with new NGK or AC delco plugs of the proper heat range and inspect the plug wires and replace if needed new wires are always a nice touch on a tune up . put in 2 cans of seafoam with a full tank of premium fuel , give the throtle body butterfly a few shots of carb cleaner (both sides open it )to remove some carbon (don't over do it ) start your truck and watch as it smokes like a train .than after 15 min go and drive it like you stole it . after you get down to a 1/4 tank change your oil. you may also want to clean your MAF with some eletrical parts cleaner spray . and don't forget to use anti seize compound on the plug threads (just a very light thin coat ). if that does not cure it you ether have a suspect MAF and you should get it tested B4 you replace it . if you have a MIL (CHECK ENGINE LIGHT ON) SCAN AND READ THE CODE FIRST b4 DOING ANYTHING GOOD LUCK . AND CALL OUT THE OLD GIRL AND LET HER WATCH THE SMOKE SHOW . GOOD LUCK . SOME TIMES A BAD INTAKE MANIFOLD GASKET WILL BE THE CULPRIT .