Does this sound like a bad O2 sensor?   Symptoms -- 1985 Runs fine at
a cold start.   Often, engine runs flawlessly when warm.  Sometimes,
however, it seems to get "moody"  -- it stumbles or feels gutless
when accelerating, but this usually will clear in 5-10 seconds.
Sometimes the idle drops too low and threatens to stall (automatic
tranny).  If you attempt to compensate for the low idle by turning
the idle adjuster screw, you are likely to later have it idle too
high and surge at 1500 rpms when decelerating.  Since it's recently
had a new engine, distributor, coil, ECU and DIS installed, I'm
thinking there aren't many parts left that could cause this.  The AFM
is a rebuild from about 5000 miles ago.