Truck is a 98. 5 24 v 5 speed 3500. supper chip set on tow safe,otherwise stock. The truck is used for towing a 3 car trailer . Usually has a gross weight of about about 23-27k. The truck seems to run fine but after its been at highway speed for some time (70 mph) upon slowing down to lower speeds after a few mins it will go dead pedal and act like its shut off. This is potentialy dangerious as its usually in town or constrution zones. All electrics stay on and fuel presure remains good . There is no responce to pumping the pedal for a few seconds (5-10) then it comes back to life and runs fine. The check eng light comes on and it throws the fallowing codes P 1693,P1698,J1850,P0121,P0602, I have been to the chrysler dealer and the cummins dealer and they offer no solutions . This condition comes and goes but is getting more frequent. I need to get this solved. Im tempted to buy a new VP44 ,Map,and what ever else may be the problem but Im afraid of spending a couple of grand just to have the same problem. Iv looked up the codes ,so has the dealer and cummins. No conclusions from anyone. Truck gets the same milage now as it did before this happened(8. 5 under heavy tow at 70 mph). No smoke,bucking or hesitation,good power. What is a good plan of attack? Thanks Otis