98 p 38 won't rev above 2000 rpm

Hi

I'm looking at purchasing another p38 after selling my modded 98. What I know (sight unseen) pretty clean 98 4.0 114k miles. Owner says it starts right up and stays running but doesn't hold fuel pressure? and truck will not rev above 2000 rpm. I'm thinking tps or crank sensor? Maybee fuel pump, pressure reg or vacumm line? Any other thoughts ? If the price is right i Might roll the dice? anything major someone can think of? My last 98 rode like a dream and I talked to a p38 owner tonight so of course I'm jonesing for another rr.

thanks

Jacksonbase

Ps the owner has taken it to the local goodyear? store for a fix they think fuel pump but I suspect mechanics haven't worked on a rr before