I just recently got my old free 240 running and i am still having a problem with it.

It idles fine. Starts right up. When i acquired it, it had a bad amm. The problem seems to be a rich running scenario under load...

When i plugged in the bad amm it would immediately act like it was running rich and you could get the car to rev but if given to much throttle it would go rich and die.

I went and swapped a known good amm. It started right up and reved freely. It seemed to get really really hot though like the hotwire in the amm stayed on way to long, even after just turning on the key. Thinking i had fixed my problem i took her for a spin. She ran decent for a few minutes but there still seemed to be a threshold of being able to run smoothly vs too much throttle and then it stutters and cuts out. This morning the threshold is back like it was earlier. If you back off and barely apply any throttle it runs smooth again. Give it a 5 % more throttle than it needs and it stumbles and cuts out. I have replaced the plugs, amm, main fi relay, 25amp fuse. The exhaust needs help it is about 5 feet long consisting of a downpipe, no cat, and 5 feet of pipe with a rusted resonator. The engine has 225k miles and seems decent. I have yet to pull the new plugs to look @ them. The last set were really black and carbony... There are many 240s @ the pullapart auto salvage and i am running out of ideas. What do you guys think? I am going to jumper the fuel pumps to run constantly and see if this helps. Any other suggestions?