I have a 1999 Gmc s-15 sonoma with a mild engine knock on cyl #3 on 1999 GMC Sonoma

When the engine is fully warmed up the noise almost goes away! We have pulled the motor and dis-assembled, all wrist pins are a little loose but #3 isnt any worse than the other 3.Also all rod bearings look good, and the main bearings on each side of the #3 rod look ok. All pistons mic to be standard size. Are there any odd causes for this type of noise in this year model motor? Please HELP!!!

Asked by for the 1999 GMC Sonoma
Why do you say #3 is the problem? How did you test,pull
Plug wire while running? Or something else.
1st answer ask about a rebuild,i missed that part.
Pulled plug wire also stethoscope test its Def coming from 3 no rebuilde yet just diagnosis at this poi.
This is a puzzle,i have been doing this a long time.Most noise gets worse in a warm engine.
I know a machinest/motor builder, been doing this a long time too.I'll ask this wizzard and get back
if can help.Something is expanding and then fits better.
1 more answer , 1 more comment
Interesting one...did you use oe parts for rebuild or aftermarket?
Haven't rebuilt, just tore down to check valves,guides,pistons,rings,etc.