This has just started happening. I have a '88, F150, Lariat XLT, 302 w/ EFI. The truck starts and runs fine in the morning, or after sitting for a couple of hours. However, after about fifteen minutes and warming up, it starts to miss. Not like a fuel problem, both tanks and pumps have been replaced. More like an ignition problem, like a loose wire or something. I thought the coil was breaking down, so I replaced it. Same problem. Had everything checked about 3000 miles ago (plugs, wires, codes, etc.) everything was fine. I'm stumped. Anyone got any ideas? Thanks.

 

Possibly the ignitio module. I had it go on my truck. It eventually would just stop running and then start right up after a few minutes.

Could be as simple as a loose spark plug wire or a cracked wire.

 

Thanks RB. I'm going to check that tomorrow.

 

I've been doing some reading tonight. Anyone think it might be the TFI?

 

Thx all. Changed the TFI, problem solved.