So my misfire nightmare is still alive. After replacing my intake manifold gasket last week I had a cylinder 6 misfire. A compression test was done before I did the gasket and all cylinders are good. I replaced my plugs, wires, cap, and rotor today and I still have the misfire code. I also checked to see if the distributor was a tooth off so I checked that and its still throwing the misfire code (code was cleared). I topped the tank off with fresh gas because it has been sitting for almost a year. Its only been driven 20 miles since the code came up. I didnt want to drive it much because the check engine light started flashing after it warmed up under load. The truck ran better when it was cold earlier today after the tune up, and once it warmed up it started stumbling a bit and the light started flashing on the way to the parts store. I'm almost out of ideas so any insight is much appreciated.

Also I did a visual spark check on #6 and arc looked strong

 

I think it may be my distributor timing. Unfortunately I am finding several different precedures for setting tdc distributor timing. Some are saying the rotor should line up with the "6" mark on the distributor, and other are saying to line it up with #1 post. Also is there any kind of trick to get the oil pump shaft lined up because its really starting to anoy me

 

I checked the distributor timing and its spot on. I'm starting to think it might be the poppet on cyl. 6. I was fine before the intake manifold gasket went, but it still could be bad. also my jimmy sat for almost a year with not power supply, could possibly the timing advance be off. I had a generic scan tool on it an the timing advance at idle was between 18-21 degrees. I'm pretty sure the advance should be around o degrees. Anyone want to chime in on this?