Larry,

It is good to have a known baseline, so a basic tuneup is a good call. My concern was the carb had already been swapped with no improvement, more of the same might just lead to frustration.

Combining our collective advice: looking at the parts coming out during a tune up and a bit of testing should yield insight into the problem...

Kevin

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...