I'm a first-time poster. I've got an '87 Ford E150 Club Wagon with a 5.0 v8. Two well-respected independent mechanics have come to the conclusion that my problem is in the wiring harness and that I need to isolate each wire going into the computer and check it for resistance, using a certified Ford schematic as a guide. Does anyone know the best place to buy the schematic and have any tips on doing this procedure? The van runs too rich is the problem. It belches black smoke, and runs so rough I can't drive it more than a few miles, as it dies often. The plugs get fuel-fouled fast. We changed the computer, the MAP sensor, the fuel regulator, the temperature sensor to the computer, the air temp. sensor, the rotor, the ignition module, the O2 sensor, the water pump and the timing chain. The ignition timing was set. Nothing helped. The problem happened suddenly. I was driving with the engine well-warmed-up and I pressed on the gas and the van all of a sudden had no guts, going 15 mph with my foot on the floor. It also kept dying in intersections (at low rpms and mph's). The first mechanic told me the catalytic converter was bad, as the exhaust was weak. He said it idled too well for it to be a fuel pump problem. I pulled out the O2 sensor temporarily to get me home. I could then build up to a speed of 50 or so, although driving at low speeds was a challenge. When I got home, I cut out the honeycomb in the cats. I drove the van for a few days. It didn't have it's usual power, but worked okay, until it stalled. When I tried to start it, the cranking sound was different. My mechanic came and checked the compression and found it to be zero. He changed the timing chain. But the too-rich problem continued. Then we changed the other things mentioned, one by one. Before a couple weeks ago, the van ran reliably for me for six years. It has 132k miles.