misfire and bad smell when hot

At temps over 210 my 96 automatic XJ starts to idle rough and there is a misfire accompanied by a fart smell coming from the exhaust and a pop pop pop sound at the tail pipe.
I replaced my cat a year or 2 ago and it behaves fine. I would think it' san injector but the fart smell I think is uncombusted fuel, so would that point to spark at that cylinder?

Where do I start with this? I'm over loaded right now and just need some direction. This misfire happens in traffic jams which there are a bunch of when I got to work starting tomorrow and want to feel safe and not like I"m gonna ruin my only rig.

The smell can be because it is running too lean and that will cause it to run hot.

Would plugs gapped way too far apart do that?
Just pulled #1 and it's gapped like .06-.07 :wierd:
Changed distributor cap n rotor yesterday, no change. Changing out wires and plugs now. What is PROPER torque on the plugs btw?
FWIW it seemed like, when hot, number 4 injector wasn't ticking as loudly. Might be in my head. ??????