cold start up knock?

**eric69cam** · 11-12-2006, 07:25 PM

i have a 2000 silverado with a 5.3. it has what sounds like a knock for the first 20seconds or so on start up.

i've heard from a few people i know with as little as 30,000 miles that theirs does the same. does anyone know the problem? any help would be appreciated

**RandyW** · 11-13-2006, 03:38 AM

My Tahoe developed it at about 80000 miles. It was just carbon build up, though I don't baby it. I towed a car through the mountains and mine went away, I guess the extra heat and rpm broke the carbon loose and cleaned it out!

**eric69cam** · 11-13-2006, 07:49 AM

well i can't really say i baby mine at all. i tend to have a heavy foot. it just seems to be pretty stubborn. i am in the process of changing plugs and wires. wires are done through msd. just waiting on the plugs. i guess i'll see what that does for me. thank you though

**RandyW** · 11-13-2006, 10:17 AM

I never babied mine either, but it still had a major carbon build up, the best way to get rid of it is to 4 wheel in deep sand or tow a heavy load at high speed up hill.

**chevyguy789** · 11-13-2006, 12:54 PM

you may want to check out another forum. i often check out pickuptruck.com

do a search on cold start knock. you'll find many remedies of what other people have tried.