I have a 2002 Ram 1500 4x4 with the 5.9. It has been idling rough and hesitates to the point of almost losing all power under load when cold. After punching the gas several times or babying the throtal over a 1/4 mile it seems to run fine until it sits about 8hrs and cools down then the same scenerio again. The gas mileage is around 11.2 not sure if that is normal for a magnum 5.9. I changed cap, rotor, plugs, wires (all oem replacement) iac (twice not sure about first one seemed like plunger was extended much further than 2nd one) tps (twice just for giggles). i cleaned the TB very well including where the iac sits and all vac ports. Checked the infamous pluenum no oil detected and no leak in intake (sprayed carb cleaner on outside) evap lines are good and charcoal box is not spitting any debry into lines. Im almost at a loss with this thing. Im still driving it daily. I have not yet tested pressure on fuel pump but Im not sure that is the problem i poked the needle on the test port and seemed to have plenty of pressure after warmed and cold (after sitting over night check valve seems to be holding). I also dismantled the fuel rail and all injectors and cleaned them very well. No codes stored. Please help it seems there are a lot of people with a similar problem and no one has come up with a solution................yet.

 

seeing you have the 5.9 you might want to post in the 2nd gen section also.

 

Thnx for the advice