I have a 2000 dodge ram with 318 that has been acting weird at highway speeds, it acts as if it's running out of gas, when it's acting like this if I push pedal it backfires and pops out of intake, cruising around town at low speeds it doesn't act up most of the time every now and then it'll have the problem at lower speeds, i think it might be fuel pump or regulator, I thought it could have been the cat clogged up, throwing o2 code so I checked and the guts have been knocked out so I checked muffler for it being stopped up problem persisted even while disconnected it was just louder, I checked my fuel pressure and when the key is first cycled before starting truck the pressure spikes around 48 psi and starts dropping back to zero, once truck is started the needle constantly bounces from 45 to 50 psi, it does same thing even when weird shutter happens doesn't change just same fluctuation, I'm unsure of where to go from here wanted to get input before I put a new pump in it

 

Welcome Aboard 503615! Stay tuned - a Technician (or member) will jump in shortly to provide a possible solution. In the meantime, don't forget to browse Sub-Forums: 2nd Gen Ram (1994-2002) for stuff related to your ride.