I have a Vortec 4.3 that knocks and idles roughly when I start it, especially on cold mornings or after it sits for a while. The knock seems loudest over cylinder 1. I ran engine cleaner (Gunk) through it once and it seemed to solve the problem. The knocking returned 1000 miles later. Put Gunk in a second time, changed the oil, and is silenced the noise until about 750 miles on the new oil. The engine has 76K miles on it. What is going on and about how much would it cost to fix it?
Jan 18, 2006 at 2:52 PM