Have you advanced your timing at ALL? Or messed around with your engine alot? Also I know you said you changed the oil (or had changed) but did you actually check the oil level a few days after? A friend of mine was due for a oil change in like 1k miles, but to his suprise, after his engine started knocking there was no oil in it. Ruined a Oldsmobile Aroura that way, had a V8 32valve 4.0 cadillac northstar engine that way. I know that prolly isn't it but it was time for a story
