I have a 99 dodge cummins with 85,000 miles has hypertech programmer and bully dog 5 inch exhaustI recently replaced fuel filter when realized the lift pump wasnt pumping, replaced itThe problem is when the truck is cold it cranks goes into gear fine drives fineafter truck warms up it will cut off while idling in gear doesnt start back as good a normaltruck does not show any codes thanks for ANY help

Have you checked the truck with an ODBII scanner because I don't believe that the 99's did the key trick if I am not mistaken.Also what is the fuel pressure at?Beyond that I am going to say that if the problem is only present when warm it would be best to see what is going on with a scan tool so you can see the temperature sensor readings.There is always that possibility of a dead VP44 but I wouldn't jump to that until we see exactly what is going on.

Cummins 2K is right you need a code reader. But I would pull the error codes and then get a fuel pressure gauge and check the fuel pressure. Error Code Reading... http://mopar.mopar1973man.com/cummins/2ndgen24v/obd2-error-codes/obd2-error-codes.htm Fuel pressure... http://mopar.mopar1973man.com/cummins/2ndgen24v/fuel-pressure/fuel-pressure.htm Now as for the hard starts that caused by the low fuel pressure. You tore the diaphram inside the VP44. The only choices you got now is build a small mod or replace the VP44... The mod is at the bottom of the fuel pressure page...

I have not checked fuel pressure , I willI have checked for any codes and there are none After it warms up and is hard to start you can unhook the ECT and it will sart quicker

Next time the hard start occurs try unplugging the fuel pump. If it fire up right away then you know that fuel pressure is too high for the hyper-senitive VP44 because of the torn diaphram. Fuel pressure is a key issues here... You need to see the cranking pressure as well as idle and WOT on the highway.