My truck vibrates when driving, in 3rd gear (when locked up...AOD); goes away upon acceleration or downshift. After a few forum posts, most seem to think i have a slight misfire that causes engine shake and transmits through locked up torque converter. The truck engine also shakes slightly when warmed up and in Park/Idle/900rpm. It's not a performance engine, stock 5.0EFI. So I'm going w/ the misfire theory, couple questions regarding isolating this:

1) If I had screwed up the firing order, that would be majorly noticeable, right? ( I've checked a bunch of times I know it's non-HO firing order. but...my eyes are getting older..)

2) If I pull individual plug wires, would that tell me if a cylinder is not contributing? Can truck run w/ a plug wire pulled? [I'm leaning on trying this if worthwhile]

3) Truck is a MAP sensor, and I'm pretty sure batch fired. Would a NOID light help me? I've pierced the wires on each bank and scope shows strong even pulse train, so unless I've got some injector wire fault out near each injector, not sure what this would buy me.

4) Could it be a lifter that's lost prime on one cylinder, causing out of balance cylinder performance? Could this be detected with a stethoscope?.

I've checked compression and varies between 170 and 182 psi Just looking for ideas on isolating a misfire.
Best Regards.

 

Does it misfire right from a cold start or is it only after it warms up a bit?

 

I would say it's more pronounced after warm up. I notice that the engine shakes slightly at idle and can hear a slight ticking noise after I've driven for awhile and puill it into the garage.

 

Was this before or after the tune up, miles on truck, could be coil breaking down once warmed up, make sure, exhaust manifolds arent cracked, could be crack, opening up more once warm.