All right in the past when my idle has dropped two low I jest tighten up the throttle linkage adjustment when I looked in my repair manual and read up on it you guys talk about a low idle adjustment screw but I cant find it can some one help me

 

its kind of a pain to find...
with the engine off stick a screw driver in the linkage to pull the throttle wide open...feel around just to the left of the primer bulb....i just feel around for a piece of threaded rod. you will not be able to see it. It's easiest to reach under the brake master cylinder and equip yourself with a 10mm end wrench. You will find it, its just kind of hard to explain

 

Idle should be 800 rpm with truck in gear (or drive) with AC on.

Idle adjustment is a bit on the painful side. The first time will be the worst. The adjustment screw is on the back of the injector pump, you have to do this blind as you wont be able to see the screw. If you get under the truck and look up at the pump youll see it:

http://www.dodgeram.org/tech/dsl/adj...d_Gen-Idle.htm

Theres plenty of info here - just do a search:

https://www.dieseltruckresource.com/...dle+adjustment