It's a 2005 3500 dually, 5.9L cummins, 6spd, 2wd. The truck runs, idles, and drives great. The only problem is when I shift out of gear and the motor goes back to idle the rpms drop to about 600 rpms, shudders, then revs back to about 900 rpms before it resumes regular idle at 800 rpm. It almost feels like the motor shuts off then catches itself before it stalls. Shifting between gears it runs fine, no lag or hesitation. The only time it has a problem is when it goes back to idle. Does anyone have any ideas or experienced themselves? I'll take any help I can get. Thanks.

 

Sounds like a funky FCA to me.....my '03 use to do the same thing way back when.

 

Thanks for the help. Ill try it out and see what happens. I appreciate it jhenson.

 

Keep us posted!!

 

Have the same problem with my truck!! I put on a new FCA from Cummins, didn't change a thing! Let me know if you find anything that fixes the problem! I did read a thread on here about a wire that is somewhat unprotected under the AC compressor rubbing on one of the AC lines and causing a short to the ECM, causing some funky running issues. Haven't had time to check mine yet

 

Have you done anything else to try to fix it? I had someone else tell me it may be the FCA, so I'm gonna try that first. The only thing is that I cannot find it on Cummins. Do they call it a Fuel Control Actuator or am I missing something? I might just be a little dense in this area, never ordered parts from there. I appreciate the help

 

Ramminva, I did look at those wires by the AC compressor. Sure enough they are unprotected. Mine weren't frayed yet but pretty close.

 

Yes, it is called the Fuel Control Actuator. If dealing with a Cummins dealer all they need is the engine serial number and they can get any part for it. GenosGarage.com also offers them.

 

I need to check the wires under my ac compressor now. I looked at it last week but it was in the driveway in the dark with a flashlight and i really couldn't tell anything. Your problem sounds exactly like what I'm dealing with. Put on a brand new FCA from cummins (i'm pretty sure thats with cummins called the part), also took it to the dealer because mine was still under warranty as of july but now its out, they did a reflash of the computer with updated software, that did nothing. They pretty much told me they couldn't find anything wrong and that I was wasting my time. But I don't think I'm wasting anything because I know its not right. I've rode in trucks exactly like mine and they don't do it.

 

cbd009 If you ever find a fix for your truck PLEASE let me know! It doesn't feel like it really takes anything away from the truck as far as power or anything like that, to me its just annoying more than anything.

 

Will do. Im the same way truck runs great, just annoying feeling it do that every time I roll to a stop. I've been looking everywhere and asked around, but nobody seems to have a straight forward answer. Thanks for the advise and I'm gonna ask around a little bit longer before I order the FCA. I'll keep you updated.

 

My truck has just started acting the same way and was wondering you anyone has found a fix yet.
Thanks

 

Mine has started doing the same thing...2005 3500 dually 272,000 miles..anyone come up with anything yet?

 

I was able to make it to Cummins today and picked the new FCA or MPROP as they called it..$110.00 Very easy to remove and install.
Truck runs great now and holds the RPM steady. Hooked up my Smarty and found that I did have a p0191 code for the fuel rail sensor.
Cleared that and it has been driving great.
I used a magnetic extension with a t25 torx tip and a ratchet drive. The extension was one you would use to make a screw diver reach farther... IT worked great to get the angle correct to get the screws out.
It took about 20 minutes and I was up and running.
Good luck

 

I got the FCA in and replaced it last Wednesday. There has been no change with the problem, driven 300 miles since new part. If anyone finds a fix please let me know. Has anyone replaced any other parts chasing this problem? or have any other ideas? I appreciate any help.