Quote Originally Posted by 01gpgt01 View Post
I wouldnt go mix matching heat range on plugs. These cars are notorius when moded at having mis and surging during closed loop operation. Some people have had luck with tuning.
No mods on this engine... that I know of. Just came out of a plug/wire/oil change. Just for giggles & grins I'll have the 'puter reflashed and see what happens.

As widespread as this #4 misfire seems to be on the 3.8 it's surprising no tech bulletins or fixes have been found by now. I do a lot of multiple stop daily driving and if it weren't for the closed loop miss on restarts I guess I could live with this particular gremlin. But just knowing the engine is out of balance for a few minutes and remains an unresolved problem bugs the crap out of me. ~FH