the participation on this site is super. i've read many posts, and tried / tested several possible problems, but still haven't solved what's ailing my 1984 240 wagon, 177k miles, 4spd, non-turbo.

the symptoms:
the car starts and idles fine, every time. after driving 5-10 mins, there is a drastic loss of power, and i limp home.
the temp guage reads very near the red when this occurs, but levels out again at idle.

what i've tested:
1. the wiring from ecu to amm tests intact, and the harness looks o.k.
2. the resistance at the amm tests correct, but i tried a replacement amm anyway, no change.
3. the air box valve was stuck open, now it's closed, no change.
4. tried a replacement ecu, no change.
5. filled the gas tank full, no change.
6. i can hear the fuel pump in the tank and feel the fuel pulsing at the injection.
7. the cat was replace by the previous owner about 20k ago, along with the fuel pump relay.

what's next?
thanks in advance,
jstarr