93 with 3.1 stumbling

Howdy. Was coming home the other day and about seven miles from home the engine started stumbling. It was like I was tapping the brakes and the service light was flashing. Had to feather the throttle at all stops. Next day started just fine and no light. Took a couple of 30-40 mile trips, no problems. Went to family reunion, about 350 miles, and 50 miles from home it started again. It stumbled a couple of times then WHAM. It was like I slammed on the brakes and the service light stayed on. It let up but continued to stumble the rest of the way home. Had to feather throttle at all stops. Tried to start it this morning and it didn't want to. Had to pump gas to get it started and then it ran kind of rough. the service light stayed lit. The first time this happened was at 65 mph on cruise. The second time was at a constant 80 mph. Any thoughts/idea's on this? Thanx.
Mike

The flashing light you are seeing is signifying a misfire (although a code would help distinguish from where). So either you are missing spark, compression or fuel. With the age of these APV's I would first look to the fuel pressure. You can check it when it is not doing it and see if the pressure is low. Also have the gauge with so you can check it when it happens. If that checks out then I would move to spark.

check all spark plug wires and connections.

Thanx for the replies. You won't believe the cause. I replaced fuel pump last year so that shouldn't be it. Replaced fuel filter, not it. I thought i'd check fire and pulled each wire while running, not it. While motor was still running, I was messing with the plug wires when I found a burned spot on one. Yeah, it lit me up! Put new wires on, didn't help. When I put the breather back on, I noticed a bug carcus wraped around a stub sticking up from the bottom. I pealed it off and now it drives just fine. Come to find out that stub was the MAP sensor. Murphy's a pain in the a** sometimes.
Thanx again.
Mike