Ive been chasing this light throttle under load knock or detonation for awhile.
I was looking at Long term fuel trims and noticed they where high. Smoke tested and found a major nasty leak at Brake booster line at Throttle body collet/seal.
Replaced, fuel trims dropped, starts quicker . brakes better AND knock appears to be gone. Must have been a lean tip in detonation when warm.

I will push it hard this evening and let you know how it turns out.

 

 

nope...still there after highway driving.then stop light to stop light. Starts the clatter/knock still. I'm wonder if it is a coolant flow issue? At idle this morning I was getting 98C which seems slightly high? Right? Guage mid scale. I may replace water pump and t-stat tomorrow.

 

So you are SURE its not timing chain clatter, right? And you are burning 91+ gasoline?

 

Not chain clatter.All replaced with metal..I run 93 shell and Exxon. I have new pumps and filter.

some guys with Autologic in the UK said may be a converter.. Not so sure.

 

You mean a clogged cat converter ? Is there a fairly simple way to test for that ? Maybe a vacuum guage ?

 

Im going to check it but does not run like a clogged cat,