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

 

check this out. https://dodgeforum.com/forum/2nd-gen...um-thread.html

i wouldnt go right to the fuel pump yet..

 

When I was checking sensors and vaccum lines I check down in throttle body, didn't see anything that would cause me to think the gaskets were bad

 

Failing O2 sensor? Try just unplugging the sensor, and take the truck for a drive. See if the problem goes away.

 

And just looking down the TB doesn't mean anything. You need to remove it, and look around inside the intake manifold with a light and a small mirror.

 

Well I unplugged the o2 sensor, it's running ok, buy since the problem is intermitant, im gna drive it for a few days and see if problem returns, I'll let ya know if it stays running ok thanks for input

 

Well I just went and drove truck I had just check codes and no p0108 went and ran truck it did it's stutter thing and then when I checked codes at home got the map code, could my problem have caused this or would the map sensor be causing the problem