1997 Dodge Ram won't take gas - misses

When driving, my truck won't take gas it misses. It does this randomly and when climbing hills. I noticed the problem a few days after driving through extremely wet/muddy/clay/dirt roads.

Recently at the end of a 6 hour trip my truck wouldn't take gas, go over a certain speed, and the engine revved up on its own (rpm needle jumped) without the truck physically accelerating.

Had it tested - computer reported the speed sensor. I want to have it fixed but want the correct thing fixed. I've been told it was the transmission - got a second opinion and was told it was the fuel filter, possibly the pump.

Service record:
2005 Transmission Filter Replaced @ 248,494 miles
2005 Replaced Alternator @ 252,606 miles
2005 Replaced Fuel Pump Assembly @ 245,687 miles

Thanks in advance,
Staci