Have 96 2500 with the 5.9L and having a small problem. It starts and Idles fine but lately it has been getting worse. It ocasionally will die when I let off the gas pedal but yesterday it would not even stay running idle. Other than that it runs great when it is running. The only time it has ever done it is when it has been sitting cold motor.Even if Ilet it idle for 15 miniutesit will die soon as I let off the gas pedal.
Any suggesetion would be great.

 

Could be the IAC valve. They get all gunked up up sometimes. You can take it off and clean up good with some throttle body cleaner.

 

that happens to me when i let my batt. get to low, like if i leave my amp on and don't drive for like 2 days.

 

yank off your TB and clean it and the IAC real good... 99% of the time this is the cause of the problem.

 

A bad battery can cause that. When i did my ball joints, i left the key in the on position the whole time and forgot about it. It drained the battery and i had to jump start it. It never ran right until i did a slow charge on the battery.

 

mine did that, exactly what you were describing.

ended up being the coolant temp sensor of all things. good luck

 

1. Dirty IAC

2. Weak battery/bad connections - Could be caused by a dying alt, but probably just dirty connections

 

could adjust your throttle cable too..