Can't figure it out...
 

1994 4.3L auto(4L60E) about to turn 160k

I did a tune up last week. Ran great before it, but it was due. Plugs(Bosch Plat 2 gaped .045 as said on fan shroud, wires, cap, and rotor.

Got everything done and fired her up, started right up, 2nd turn over which is normal. Driving home from the shop she started running rough. (I think I'm dropping spark on a cylinder on the right bank) If i get on it it smooths out, for the most part it is smooth at idle. Not displaying check engine, not throwing any codes.

The following is what I've done so far:
1. I ohmed out the coil pack = it was good.
2. Don't think its a vacuum leak = doesn't die at idle + map sensor is a 2 year old AC Delco. All my lines are good, from what I can tell.
3. Changed out the the ignition module on the distributor.
4. Pulled the plugs = Porcelain wasn't cracked, carbon from firing was consistent on all.
5. Fuel system, I'm unsure about??? (but don't think this is the problem) = Why would this only happen after a tune up?
6. Bad set of new wires??? = Going to put another set on tomorrow morning.

I have to go out of town next week. In my truck. I don't feel like having a major issue on a TX country hwy.

Any further direction would be greatly appreciated.

RE: Can't figure it out...
 

We had a Chevy Astrovan that did the same thing as I recalled. And after replacing all the wires, plugs, cap, rotor, cleaned injection system, etc... We came across the engine mounts had gone bad. Lik I said though it sounds like a similar situation I remember, but that was like years ago so my memory could be a bit off, but it is just a check under the truck to see... whats it hurt?

RE: Can't figure it out...
 

They seem like silly possibilities, but maybe the cap or rotor is on loose/crooked, or a plug wire isn't fully seated?