Originally Posted by 2kg4u
You have addressed the obvious potential causes. I would check fuel pressure next. A failing pump would give a random misfire, but since you already did everything else ...
Check for spark on the #6 plug. That will tell you if the issue is spark or fuel. Could also be a mechanical internal issue, but we are not there yet.
In case you have a bad plug, switch #6 with another.
Seems to me the #6 wire runs near the front O2 sensor. Make sure it is not rubbing
Good suggestions, Don't even want to think fuel pump. plus it is specific to cylinder 6. If it was the pump wouldn't it be random misfire on all cylinders?
I was thinking possibly a bad injector?
I am going to start with re=torqueing the upper and lower intake bolts with a real torque wrench. if that doesn't do the trick I am going to install a new plug, if I have to go any further than that I will switch #6 plug wire with #4 to see if the problem follows. I think I will also switch fuel injectors from one cylinder to another while I have the fuel rail off.
I'll update my progress sometime Sunday