So I recently bought a 98.5 2500 with 24 valve Cummins and automatic transmission. The truck is in very good shape for the year and the engine has good power and seems to run smooth. My only beef is that it idles at 900 to 1000 rpm. I took it to the dealer to check out the idle speed and adjust it. I'm away from home this week so the service manager phones my wife and says that the only fix for the idle problem is to replace the PCM or the TPS, either of which will run about $4k. I've been doing as much research as I could on Ram/Cummins trucks before and after buying and from what I have found this truck doesn't have a TPS but rather a APPS and not one reference to a faulty APPS causing high idle speed. Now, I don't usually take anything to a dealership, doing most repairs myself, but this is my first Dodge so I thought I would give them a try. I could take it to a Cummins dealer or mechanic with Insite but I also wanted the transmission serviced and bands adjusted and I don't have time to do it now. The guy I bought it from thinks that the guy he bought it from had the 3 cylinder cold start enabled and it had idled fast ever since. It has a Van Aaken controller installed and I unplugged it to see if that might affect idle speed but no change so I plugged it back in.

Any opinions on idle speed, and the TPS/APPS? What is the likely cause of fast idling.

 

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