I just finished a custom mass-air swap in my 87 F150 this weekend. I used a mustang ECM and custom wired the engine harness. The truck has awesome power, but there are still a couple of bugs to get worked out. I have to figure out how to pull the codes, because the method for the trucks didn't work. I also have to figure out what causes the stumble when I hit the gas at idle. I went from my house to the gas station, filled the truck with gas, then when I tried to restart it, it just spun over and didn't start. I thought I had maybe gotten something wrong and messed up the computer, but I still had spark and fuel. It eventually took me rotating the distributor as someone else cranked the truck, and it fired off and ran. So I drive it home, double check some things sitting in the driveway then I drive it around my neighborhood. Get back to the house, cut the truck off, and then crank it right back up, no problems. I went and did something in the house, came back out, and it didn't start again. So I left it sit there, and came back when it had fully cooled off, and it fired right up once again. I'm thinking that if I can figure out the codes, I will be able to pinpoint what might be causing this problem.

This swap was pretty straightforward, but it took a couple of days to get the wiring done. I checked and re-checked the wiring several times, and it's dead on. I really gained a lot of power - I really wasn't expecting to gain anything, so I was pleased there. The truck felt the best it has ever felt, so I think once I get the couple of bugs worked out, it will be a very smooth running engine. I've got a few pictures, I'll see if I can't get them posted in the next week or so.

 

Well, it sounds like you are using the old igntion module mounted on the distributor, I would replace it as that it what it does when it's starting to fail.

 

Thanks pfogle, my TFI is mounted on the distributor so I'll definitely look into that. A friend of mine knows somebody down at the local Ford dealership, and they told him the same thing.