My 94 F150 has a straight six. For a couple of months has had an intermittent problem: Check engine light comes on, engine idles very rough and cuts off, runs rich as heck when this happens. I've replaced the IAC, MAP, air temperature sensor, coolant temp sensor, fuel pump relay, and EEC (I think) relay.Replaced plugs, wires, distributor cap, fuel filter. Still the problem occurs. Only once did I get to the mechanic in time to get codes, and they showed the air temp sensor (which was replaced as noted) and the computer (checked the contacts, there wasn't any corrosion). Could this be due to the fuel pressure regulator being intermittently cutting out? The intermittent nature of the problem is making me and now the second mechanic who is working on it crazy.
Thanks for any suggestions.

 

Finally, the check engine light stayed on the entire time I drove to the shop. My mechanic said the truck was showing a code for every sensor on the truck. His conclusion was that it was likely the computer. I'm not convinced and expect I'll still have intermittent problems. But maybe I need to take a more positive view.