Hi folks, I'm back.

1992 Volvo 240, LH 2.4 fuel injection, auto trans, 262,501 miles and climbing. This car sat for three years, and I bought it in July. I have slowly been going through it, and now down to the last problem. The engine idles steadily, but has more shake than my 1993 with the same fuel system. Upon acceleration from a stop, it is a little rough but will smooth out as speed is gained. The car will accelerate reasonably with 3/4 throttle, but I can tell there is some missing (very slight). However, if I accelerate from a stop with full throttle, the engine will flatten out (that is cease to accelerate) and not shift to second gear until I ease off the throttle. The car will easily do 70 MPH on the interstate, and in all other aspects seems to drive normally, just being somewhat anemic.
There are no codes being thrown by the electronic modules. I have done the following:
New plugs and wires (cap and rotor look great)
New O2 sensor
New exhaust except cat. Had cat off to remove pressed in flange bolts, no looseness detected.
Rebuilt AMM installed.
Cleaned throttle body, made sure orifices were clear and idle switch set properly.
New fuel pressure regulator (yes, the old one was leaking through the diaphragm).
New pre-pump, main fuel pump and filter. Fuel sock was incredibly clogged, I really thought that this was the problem.
Cleaned all FI system connectors with contact cleaner spray.
Swapped in known good IAC valve from the '93.
Checked for vacuum leaks, can't find any. Replaced flame trap due to snapping brittle vacuum hose bib off.

I know the next step is a compression check, but even if I had one bad cylinder, the acceleration shouldn't flatten out like it's fuel limited.

What am I missing?

Thanks,

Dave Milo