My 03 common rail SO often drops below 500 rpm's and suddenly revs itself back up to stay alive. Sometimes it completely dies. It happens almost every time I take it out of gear and am slowing down for a light or something else. It did it for a short time after I first got it a couple of months ago, then went away. Now it's back and it's doing it quite a bit. It only does it around idle speed mostly when i'm slowing or sitting still. It's fine under throttle. I replaced the fuel filter figuring that if it was clogged or restricted that there was enough fuel pressure to overcome the restriction under throttle. However after replacing it it's still acting up. Any suggestions on what it could be, or anyone know a place I can call? Thanks!
Adam

 

If you are fortunate enough to still have a warranty, take it to the dealer and get the codes scanned. You likely still have the original pump, and those have been replaced by a couple upgrades since that series was built. What happens is they wear a bit and start dropping head pressure when the engine is warm. That results in erratic idle, stopping when you take your foot off the throttle at a stoplight, etc. If this is the problem it generally is worse with a nearly empty tank of fuel that is warm from running, and better with cold fuel and in cooler weather.

The other thing to have checked is the rail pressure release valve. They build up contamination and will stick microscopically open and lose rail pressure at lower engine speeds. That can come and go, but will eventually just stop you when the valve simply sticks open enough to let the rail pressure drop below injection limits.

 

Awesome! Sounds like you know your stuff. I have a code scanner and none came up. I'm at about 99,100 miles right now. I called the dodge service department and they said that I still have about 1000 miles left on the engine warranty. They said that the lift pump may be covered, if in fact that's what problem is.....but I still have to drive this thing to work and i'll go through 1000 miles within the next two weeks.
The rail pressure release valve would probably be covered too, right?

I also noticed that since it's been warmer out that it's been doing it a lot more. It didn't seem to during the cooler weather after I first bought it.