Running Rough/Misfire

We have a low mileage (108K) for its age 1991 Ford Tempo (2.3L 4 cylinder). It has run great for a long time. However, within the last few years it has exhibited some strange starting behaviors. Sometimes the engine will start immediately and sometimes you can crank it for ten or fifteen seconds and it won't start. However, if you simply shut off the key and try again it usually starts right away. The car then runs just fine. At least it did.

We took the car on a long trip recently and everything was fine until we stopped for gas. As soon as we pulled out of the station the car started bucking under acceleration and running rough. It did keep running, however, and we were able to complete the trip in spite of the problem; again running at highway speeds although it was hard to get back up to speed after a stop. At first, we assumed that we had gotten some bad gas and I added a can of Heet in case we had picked up some water when we refueled. I also replaced the under the hood fuel filter just as a precaution (I cut the old one apart and didn't really see anything out of the ordinary). The car ran fine for a day or two and then we started home. Just like before the car ran smoothly until we stopped for fuel. After filling the tank the car started acting just like it had before. And just like before even though the car was bucking and misfiring we were still able to drive at highway speeds and get home safely.

We have no "Service Engine" light but I went ahead and ran the test and got "11" as the code which means there is supposedly nothing wrong with the EEEC-IV system. And as a point of reference I had replaced the Fuel Pressure Regulator at 86K miles in an attempt to help with the earlier staring issue. It did seem to help at the time. And I also replaced the EGR Valve Sensor at 76K miles after getting a code for that problem.

And today my wife got in the car for a short trip and the car died in the driveway as she backed out. She put the transmission in neutral and tried multiple times to start the car but it would not run. However, I got in the car and turned the key to the OFF position, Turned it to ON while listening for the fuel pump to come up to pressure and shut off (which it did), and then moved the key to START. The engine started immediately and I was able to put it back in the garage so I could try to figure out what is going on. We've always done all of the required service on the car regularly (oil changes, air filters, etc.) And just before the trip where the problems started put in new spark plugs.

I have wondered about the EEEC-IV Engine Control Module itself. Could it have some intermittent circuit issue that makes it sometimes not allow the car to start, or maybe make it run rough. Or maybe the two issues aren't related at all. At this point I'm open to any new ideas that might make the car reliable and on the road again.

Thank you.