i see...had be clueless for some time now, im going to grind it done this afternoon and give it a try...if nothing im going to get 2 sensors and give it another whirl..ill post results if anything works...

 

My misfire is fixed! All it took was plugs and wires. Good luck

 

wish I can say the same...I took off about 1/8th inch of the bungs ...I tried multiple 02 sensors. Still same as before, when cold @ idle I have a random misfire ( no code ) when hot it isnt nearly as bad ( every now and then ) driving its fine until you fully step on it then it will sputter a little, ( again not steadily ). It only has 56k, I put new plugs in for the hell of it. According to the guy I bought it from there was 0 problems with it until he put it into a tree. I bought it for my v6 swap. There was 0 reason for the guy to lie, he wasnt getting nay money out of it his insurance paid him I bought it from the insurance company, his info happened to be there so I gave him a call. I put long tube headers on it ory, no cats. There is nothing deleted in the engine bay ( emission related). Ive doused the engine with carb cleaner...there is no vaccum leak. changed pcv, temp sensor...just dont get it.

 

I had this problem, put in a new shortblock (#5 had a broken ringland) and still having the trouble even with new plugs and O2's at the same time as the engine. I've been using the 13111 Rear O2's lately from the Corvettes but might try going back to regular O2's and extensions.