Chasing False Knock

[BmacIL]

I had a similar sound, but on the opposite side where the flex pipe is at (stock headers). I was getting alot of false knock at WOT between bad gas and a bad flex pipe. Did 100 octane fuel, eliminated most of it, then had an exhaust shop cut out the flex pipe and hard line it and i haven't had any issues since (now on e85). Does it rattle around the flex pipe? Hopefully it's not a bad cat.

I actually had my flex pipe replaced. It doesn't rattle when I tapped on it, but I should check it again when it's running. I have tried 100 octane and the knock is still there, so I know it's false. Just gotta find the source.

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[TGGT]

I’m glad I checked out this thread! I decided to look at my passenger side header, and it’s been making contact with the frame. Looks like I’m headed to the shop on my day off to fix this. Sorry for the poor pic. It’s hard to see because of the shadows

 

[TGGT]

Problem solved! I moved the motor over as much as I could, but I didn’t feel that was enough so I heated up the header tube with a torch and forced a chisel between the tube and the frame. I have about 1/4”-3/8” clearance now. I data logged some pulls before and after. A little later I’ll check them to see what’s what

 

[BmacIL]

I'm still chasing mine. Only happens when I hit the pedal hard to WOT. If I roll on even a bit it's gone or very minimal. Shaun suggested checking the plate between the block and flywheel housing

 

[Bahndvr]

What size is the nut on the A/C brace?

 

[kluke15]

I'm still chasing mine. Only happens when I hit the pedal hard to WOT. If I roll on even a bit it's gone or very minimal. Shaun suggested checking the plate between the block and flywheel housing

did you ever figure out your knock? what headers do you have? your issue sounds like mine

 

[BmacIL]

did you ever figure out your knock? what headers do you have? your issue sounds like mine

Negative, though I haven't had a chance to get it up to really figure it out. Stock headers.

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