These very well may be separate issues, as i had a '95 Ford F150 302 V8 That had very nearly the same symptoms, and it turned out that the last guy did not adjust timing correctly...up to that point swore there was an issue with the torque converter wanting 'bang' in and out, but it turned out to be a engine/driveability issue.

Vehicle: 1997 GMC 1500 2WD autmatic, 165k miles. I purchased at 159k miles about 15 mos ago.

Symptom: slightly rough idlle either cold or warm, and at 1500-2k rpm it will have either a harsh 'mis' or it feels like the torque converter is locking/unlocking roughly. The random harsh mis is more noticeable/frequent on the highway vs around town.

What's been done replaced:

- new fuel pump and filter
- new cap,plugs, wires, rotor
- EGR
- Coolant temp sensor
- TPS
- intake manifold gaskets (it was using coolant) and upper plenum (fix a vacuum leak)
- replaced and upgraded spider injectors and replaced t-stat when intake manifold was done
- cleaned throttle body (shop did this when replaced intake manifold gasket)
- dropped the pan and replaced the trans filter. fluid was light pink, but def. not burnt, and I could tell that the filter had been replaced before. Did this when i first bought it, fluid is still bright pink

I'm leanning towards either a worn distributor, or failing coil for the slightly rough idle. I did have access to the GM scanner, and I would get occassional misfires, but not enough to make it think it was a hard ignition failure....i did this before the vacuum leak was fixed, so that may have cauesed it. I can get access to it again. I'd like to fix the miss/idle issue first.

Any way to confirm it's the dist, or ignition coil? Anything else I could be overlooking?