I am not 100% convinced that the valve seals would cause a misfire either.

Interested read about changing the gaskets AB ABLETRUCK and its seems like a cheap fix that couldn't hurt even if it didn't work.

I will check the wire connection on Cylinder 4.

The past Misfire was after a cold start.

Took it out for a ride last night and this morning and so far no misfire, it ran nicely. No hesitation or vibration at idle. RPMs hover around 700 but then drop to 500 when I turn off the Heating/Cooling system and then the vibration starts again and it feels like crap.

If unplug the MAF it runs nicely.

Going to do a throttle body service tonite with a buddy tonite to see if that helps.