Have you done a cylinder balance test yet?
Did it several times before any of the new parts. 1st CB Test noted in Reply #19.
Passed every time. Problem is only noticeable under load. 2nd gear, 20mph, 1/4 throttle.
Forgot to add: ACT & ECT are new. Did them the same time as the injectors, since easy to get to. Also upgraded the FMU for the 30lb injectors.
I'm now leaning heavily towards a fuel delivery problem, i.e., pressure is good but flow is restricted. Could be a weak in-tank pump or partial blockage of some kind, i.e. degraded rubber/cloth fuel line. Already found one like this in the FMU lines. They swelled internally blocking the return flow, raising the pressure to 80-100lbs, blowing through all the fittings at the rear. It has a 155 lph in-tank pump & a 80 gal/hr T-Rex boost pump.
BTW, the whole Thermactor issue was a non-issue. It was due to the fact that the Ford Mass Air Conversion does not take into account the difference in wiring. Most likely, this was a conscious decision on the part of Ford. 88's have no CEL, & the only ones with code readers back in 1988 would be Ford dealerships. They likely had a Service Bulletin to ignore certain service codes for certain models or maybe only those with the conversion kit. In my case, there was actually a bad TAD; just a coincidence. That's why the code reader was still generating a bad code after the bad valve was replaced.
The conversion kit is now removed, with a new mass air harness, new MAF & A9L computer instead.
Pumps are making required pressure. Will be testing flow rate in a few days.