Thanks Marty. I was coming to the same conclusion that the Knock sensor went away in Æ91, but I wasnÆt quite to that point yet. IÆll have to take a look at the TSB too, and see if his computer has been reflashed yet. I would hope it had been done by now. I only see the buddy once a week at pool league on Tuesdays, so itÆs a slow diagnostic process right now.

So far my current plan for when I see him Tuesday is to start with a tank of high test, and if that makes the noise go away, then a few tanks of regular with some cleaner should do him fine, provided the computer has been updated. If the high test doesnÆt take care of the noise, I will be back here with more info after I have poked around under the hood for more than 15 minutes.

I have sprayed water mist down a carb of a small block Chevy and Ford while running before, and that seemed to clean everything out of the cylinder as well too. Anyone ever used this method on an EFI engine?

I was leaning away from a cracked header, because like you said it wasnÆt there when cold at idle where I would expect a cracked header to show itself, but it was dark and I didnÆt look closely then, so it hasnÆt been completely ruled out yet.

As for the flex plate crack, this is a 5 speed, not an Automagic, so that wont be a problem.

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Sean