Q: 1992 Plymouth Caravan 3.3 V-6 Heavy off idle miss. Smooths out at higher rpm.

Repost w/ added info as earlier reply not helpful. Swapped ECMs were matched by year/ engine type / displacement as pre 1996 interchangeable OBD 1 style components that cant be programmed NOT OBD II or later style components that be require programming, some right down to specific VIN. Engine starts OK. Idles for a minute or so until stalls. Noted heavy modulation of IAC. As throttle is opened off of idle, heavy stumble /heavy missing occurs. Intake popping indicative of lean out condition. Engine struggles to gain any RPM just above idle. IF the engine RPM does manage to get above about 2000 RPM then engine misfire instantly &completely disappears. Above aprox 2000 RPM, Engine runs smooth,readily revs, responds normally to throttle opening. 2 used MAP sensors swapped in -No change, 2 used ECMs swapped in -No change. NEW TPS swapped in -No Change. NO EGR provision on this particular engine, as from factory. My car has 240000 miles. My car has an auto trans

My car has 240000 miles.
My car has an automatic transmission.