I recently bought a used 03 ram 2500 with the 5.7L hemi. I have noticed with it that when at running temperature my idle seems too sit at about 550. Is that right because it seems a little low? Also if I start the truck and go to clean it off the idle will change and go up and down as if someone were reving it. Any ideas as to what could be causing this? Any information about this is appreciated. Thanks!

 

Welcome to the site.

The first thing i would try is resetting the PCM and see if that helps. Do you have any CELs on?

 

Its not throwing any codes lately but when I first got it I was getting a evaporative emissions code. I took it down to the shop for that and some other things and that was supposedly fixed by replacing the gas cap. That code has since stopped. I'm going to try to reset the PCM tonight and see how that works.

 

I reset the pcm and it seems to be a running idle of about 650 now and isn't jumping around when coming down off the high idle on cold starts.