I have a 98. 5 2500, when i'm doing about 2000 rpm and try to accelerate the truck does nothing, it acts like i did not push the pedal. This will happen at low speed or high speed. Sometimes when just driving along it will sputter and lurch, like its not getting any fuel???? I did do the lift pump conversation, the one in the tank, the fuel filter was changed 4 months ago, the air filter (k&n) was cleaned 3 weeks ago. Please help! Thanks