fuel filter problems!!

I have a 1994 B150 w/3.9. The van like to shut off after driving 20-30 min. at a stop with trans in drive if i shift to nuetral the engine doesnt studder as much but the oil press gauge drops and turns red. I have had 2 different part stores give me an inline filter but the fuel filter is not inline but a canister which is giving me problems. Anyone who has had experience with this system please let me know.

The fuel filter is part of the pump assembly in the tank. It was a mid-year change for vans built after July 1993.

since my van is for work I cut the floor above the tank and put a hinged cover on it. took me ten mins to pop out the old filter and put in the new(80 bucks). I will do this access cover on any vehicle I own from now on!! If you are replacing the filter because the vehicle starts bucking when gas guage is below a certain point, I think you might be out of luck. the fuel pump is notorious for being expensive crap. However, I am going to leave the pump/filter where it is and add a cheap electric fuel pump on the frame rail. I will have to be careful that there is too MUCH fuel pressure.