Cummins M11 "Stutter"

I had a leak on the return line at the front of the head. Sucked just enough air to make it stumble.
Also change your fuel filters.

 

Take it to someone who has the Insite program & perform a cylinder cut out test. A miss like you're describing sounds like an injector failure. If one of the three originals has failed you'd be better off replacing all three. Just get it over with instead of chasing them.

 

Could be a worn out Cam position sensor? And or bad connections at the boot of that sensor.

Also check that frame rail ground cable to the starter, and all battery connection. A bad ground could screw it up too. Taking them cables off and cleaning the ground posts really good could do you some good. Keep us posted

 

We also had this stutter problem. Mechanic replaced some (or all?) Injectors and it helped a little. It is not bad enough for most mechanics to o notice but I know that when loaded it does not make the power that it did a few thousand miles ago. Just out of curiosity how many miles on motor and how much does it smoke/ "load up" when idle.

 

After 300 miles huh? Sounds familiar. Loose pickup tube gave me that problem.

I have a 1998 KW T800 w/ M11 Celect+. Not sure what truck you have but I've had problems in these areas over the years:
1. Cracked/loose pickup tube. Fuel pickup tube comes loose and/or cracked in one of the tanks. Truck works fine when the tanks are full but as the fuel level drops or as you drive around corners it will suck air. Pull the pickup tube from tank and check for cranks and check where it connects to the fitting to make sure it's tight and sealed.
2. Plugged tank vent. Rubber vent hose on top of fuel tank becomes plugged with dirt. You should be able to blow through it. One tank will become empty while the other stays full and eventually the slack tank will suck air.
3. Bad injector. Cylinder cutout test did not show the problem because the cutout test is not done under load. After many hours of trouble shooting, I finally convinced the service manager to hook his lap top (with Insite) into the data port and go for a ride with me when I was loaded. He immediately saw that one injector was not flowing correctly.
4. Uneven fuel return. There are little check valves in the return system that sense which tank has the least amount of fuel, These valves direct returned fuel to the slack tank. If these valve go bad you can get a slack tank. Replace valves or install a crossover tube.
5. Debris in tank. While this has never happened to me, I hear stories about stuff in fuel tanks that occasionally get stuck on the pickup tube.

Hope this helps.

 

Sounds like air or bad injectors. They make a injector leak kit that you plug in so you don't have to take out each injector and you can pinpoint the bad injectors. Or possibly a metering issue.

 

Does it sound like a cough?