I HAVE A 98 24 VALVE WITH 165 k miles. I am getting a crank position sensor code set. This happens only near wide open throttle. The tach goes crazy and the check engine light comes on. when checked the only code is p0331. I have previously replaced the part but the code comes back. After doing a fair amount of reading I decided to check the fuel pressure. It reads 13 at idle and will stay there until i get close to 2500rpms or so at which point it will drop to around 8 pounds maybe. the needle flutters pretty bad. The truck also at that point runs like ____.So my questions are do I need to replace the crank position sensor , replace the lift pump, or should I do some more testing before I throw parts at the truck. I am not inclined to just throw parts at it. I bought the truck a while back at a decent price just to flip but I did not realize all the issues with it. It has a 53 block and has been used to tow as it has a goose neck hitch and was a ranch truck . I had to have the nv 4500 rebuilt. I might keep the truck if I thought the block would be ok.John

Hmmm... I would try replacing the crank position sensor.As for fuel pressure that just way too low... You need a new fuel system to feed that truck.

I agree with the fuel pressure being low. Have you changed the filter lately? Mine would run rough at WOT with a dirty filter, but no tach issues. That would make me think and bad ck sensor also.