I started having a similar problem with my 2000 4.0L OHV about a month ago. The body on the crankshaft position sensor had gotten cracked and water would get in there every time I hit a puddle or went through the carwash. I can't remember which code it woudl throw when that happened, but I will try to look it up. This is a $20 part and about 30 minutes of cussing to fix.

I also had a similar problem with my 1997 F150 4.6L. Turned out that the torque converter lockup solenoid had gone bad. As I slowed down, the engine would start to bog and finally die just as I can to a stop. I could keep it running by revving the engine. In this case, I wasn't throwing any codes at all. If your check engine light isn't on, you might consider this. The local transmission shop fixed it for about $200 and I never had another problem with the transmission (the engine blew, but the tranny was SOLID!).