Hello All:
My '97 GM (190k miles) is cackling so badly in hot weather I'm almost afraid to drive it- I've switched to plus grade gas and even that isn't helping. If this was an old car you would just set the timing back a few degrees, but since the timing isn't adjustable, what do you do? Do I have to take the heads off and have the deposits it undoubtedly has scraped out? It runs like a top but I'm afraid I'm going to burn up valves or damage the pistons going like this. CN