Well my mule has another symptom im stumped about. When you put your foot on the gas to go when leaving a stoplight, etc. It moves, but the sound from the diesel engine starts out normal, then the rattle for lack of better terms stops, feels like its hesitating, wont really accelerate like it should, then after a second or so, the rattle comes back and voila, everything is normal. I notice it more after sitting for a while, versus going from stop light to stoplight. I dont move the gas pedal when this is happening, just to see if its the pedal sensor. Im suspect of the fuel pump getting enough pressure and enough fuel. Why Im thinking that is before my intake, when id set the edge attitude on 5, it would roll tons of smoke out, now with the intake on, not much smoke. Turbo boost still hits 25 easy, but not much smoke. It feels like its got tons of power, but the stop and hesitation is new. Any ideas?

 

i had the same problem with my truck, i hooked a fuel pressure gauge to the plug in the head to check the fuel pressure. at idle the pressure was fine but when under load, the pressure dropped from the factory 58 lbs to around 35 lbs (if memory serves me right). The fuel pressure should not drop at all.

After changing the fuel pump the hesitation problem went away.

 

how many fuel pumps are on this thing? I know of the one on the frame rail, but is there another?

 

there is only one fuel pump it is the one on the frame rail under the drivers door

 

last time i think the fuel pump was replaced was 100k miles ago, im sure its due, thanks! Ill get it tested.