I recently purchased a 04.5 diesel crew cab 4x4 auto trans and the truck is bone stock other then exaust mods,i have been noticeing that under light to medium throttle at about 40 to 45 mph i get a very noticeable surge as if the truck wants to go then just doesnt i dont know what to do about this as the dealership says nothing is wrong and im no diesel expert if anyone has any advice please let it flow
thanks

 

Are you talking about when the torque converter is locking up? On mine, at times, it feels as if it locks, unlocks, and then locks, like its hunting for a gear. Only happens under light acceleration.

 

If you have max load pressure in your tires with no load on the truck, the effects of the torque converter lock up are worse. Try 45 lbs in front and 40 in back unloaded. Mine was doing the same thing. After I adjusted the pressure it felt like the truck is glued to the ground. I suppose the tranny likes the extra load.

 

whats happening is when im accelerating im getting a heavy surge as if the engine is losing fuel pressure and then regaining it and so on,it has gotten worse over the last couple days and im stumped, this only happens on accel. when its cold i find that it takes a few cranks to start and when the truck is up to operating temp and driven for a while it takes a bit as well. The truck stalled out on me twice today and as soon as i turned the key off and put it in park the engine fired right back up and ran the same, im lost and im about ready to give up and take the truck back any advice would be muchly appreciated
Thanks Jeremy

 

Fuel filter?

 

Lift pump?

 

had the fuel filter and lift pump replaced, in tank pump is working ,checked out transmission and all trans feature, im still lost, boost gauge gives me a drop of 5 to 8 psi when it surges,no power tuners installed, had no issue towing a 18000 lb tractor trailer without surging and still lost

 

Any codes?

 

If it stalled it might very well have set a codes or codes.Fill out your sig.like the rest of us.

 

as per my previous post, i didnt know what was wrong with my truck. so i did what any person not know would do! i sent the truck into cummins service department and what they found was fuel pressure was dropping way below specifications at 25 - 50 percent throttle position, and every thing in the fuel system was inspected thoroughly time and time again , results showed that lift pump was failing to produce fuel pressure to injection pump