Electrical Problem

as Mountain air said put a code tester on it.

You can get a OBD-II to blue tooth adapter.. I've had about 50/50 luck with em. Hold on...
Ebay

Just plugged it into my Jeep.. Fired up TORQUE on my phone (They also have a diagnostic program but I already have Torque) and it worked.

HOWEVER.. i had one incident where Torque messed up the car's computer. it's not supposed to do that but it did. Only happened once and I was configuring the display so I may have picked an option that the jeep did not like.

Never had an issue with my older rides though

put a code tester on it. My 99 did the same thing and I move the intake around to fix part of it. Only did it when cold so don't think it was the same. As stated check the air cleaner for a nest. You might check the coil on plugs. If you have a timing light plug a spark plug cable into where the spark plug goes and the other end of the cable on the spark plug and test each plug. I had many that were on/off and 2 or 3 that just were bad. # 4 and 5 for sure since they are under the water hose for the heater and it the clamp is loose or a bad hose leaks onto the Coil on plug. Replace them I think between 40 and 50 thousand miles. My engine stop issue went away after that Except the engine stopping when it was cold and I tried to leave out and get up to speed. Just spent a little longer letting it warm up and a slow run to get back on the road. No issues after that at all. Go easy on the spark plugs when taking them in/out. The 99 was one of the engine that only had a few threads. Ensure you use a low torque on those plugs.

Might add change out the fuel filter. Located LH rain behind driver seat. You will need the little plastic tool to get it off. Always keep one on hand.

Check the air cleaner. Back then there was an issue with water getting in the intake. Ford had a TSB out on it, it worked.

Normally that would just make it cough and sputter but if it's gone on long enough it could have compromised the air intake enough to do what you're saying.

Other places to look would be fuel filters and possibly even the fuel pump.

Did it occur when you went over a bump? If so maybe a loose connection.