Originally Posted by
wiseguydave
They hooked it up to their diagnostic computer. The service tech also called and talked to Chevy...they had a tsb on it as well. Could be water or dirt or.... My friend that will be doing the work has had success in the past with cleaning out rails and even injectors. The dealer would have wanted to sell me all new replacement parts. Apparently there was enough of a mis-fire (perhaps worse before I got the car) to trip the code or whatever it does. I bought it with a check engine light and flashing "hold" light on as well as some other issues I have already solved.