I am driving a 96' 2500 5.9 Cummins diesel. It is dying during idle, but if I keep the rpm's up at around 1000, it runs fine. If I let it idle again, it will die shortly after. The batteries are new, I just replaced the relay switch, and I have a new fuel filter, and just bought a fuel pump for it. I have not installed the pump yet, but probably will shortly. Anyone know possible reasons why its not getting fuel at idle?

Thanks

 

what rpm does it try to idle at defore it dies, it may just be a low ldle which is easily adjustable, should 850 rpms in drive (not moving)with a/c on

 

It idles around 750 in park, but the truck has been idling at 750 rpm's since it was drove off the lot in 96'.

 

has it lost any power, does it start ok or do you have give it any pedal?

 

It is starting fine. If the engine is cold, I give it a little pedal. After its run a bit, it turns over fine without any pedal. The power is fine also. It even idles fine for a few seconds before it dies. When it starts to die, I can press the accelerator pedal and it will struggle back to life, but a few seconds after letting it idle again it tries to die.

 

At your trucks age, if you have not yet replaced the fuel lines, do it. The rubber rots and allows air into the system. It will get worse, start to take longer to start, and eventually not start.
The fuel heater might also be burnt out. That will allow air into the system.
The overflow valve could be getting weak.