Help-Idle Shaking the truck

[pcarlson]

Help me out if you can.



When I start my truck it will (not all the time) lope and shake the truck. Not sure how to describe it but it is like it is surging trying to stay running and if you give it throttle it will struggle to rev up. No check engine lights or codes are present or does the check engine light come on when it does this. If I shut the truck off and restart the truck will idle normally and run just fine.



Any idea what is going on? I am getting ready to load the camper and go out west and the last thing I want to do is breakdown.



I have all the current flashes that I am aware of and have only had to do routine maintenance on the truck. No issues other than this and like I said it is sporadic.



39,500 miles, Fuel filter needs replacing in 3000 miles, oil change reminder has not gone off.

 

[SNGLESHOT]

First of all I am NOT a motorhead. I always defer to the experts like HB etc. However, I see you have an 09 and assuming you may have purchased it new? If so, then you have had the truck for about 3 years at least and should have figured out a lot of the quirks by now? I had a similar problem with mine when I was going from warmer climate to a higher altitude colder climate. You didn't mention what the ambient temperature was but at night I know it can get cold in NW Wisconsin and it that was the case then maybe it was your grid heaters kicking off and on if it was below 60 degrees? That sort of 'pull down' coupled with a questionable fuel filter and an Idle Control bump might have been causing your issues. I would consider your situation rather benign and luckily so because those issues are all normal and or reasonably 'fixable'. Like I said... I am not an expert but your description brought that to mind and I thought I would comment seeing as how you had no replies anyway.
Regards
MAJ D

 

[Alan Reagan]

I would go ahead and change the fuel filter. Before you change it, feel around the filter cap and make sure that it is not wet. If the fuel filter is allowing air in, it will lope and shake like you are describing.

 

[Hoefler]

When starting in cold climates with no assistance, grid heaters, block heaters, etc. . , it is not uncommon for a desiel to lope until sufficient heat has been built up in the engine for proper combustion. It is normal and if not throwing a code or check engine light, nothing to worry about.

 

[Jim W]

Have you tried to engage the exhaust brake and the high idle feature to see if the truck will run smoother? Can you plugged in the truck's block heater to see if this will eliminate the rough idle when the engine is cold?

With a cold diesel engine I engage the exhaust brake to help warm the engine up faster. I also engage the high idle feature if I just started the truck and I need to help warm it up a little faster. But a diesel engine will not warm up sufficiently if just left at idle; you need to drive the truck. But don't stomp on the accelerator pedal just drive normally allowing the truck to warm up.

I also do not wait for a 15,000 mile change interval for fuel filters if they need to be changed because of rough idling (fuel filter could be slightly plugged) then I will change them sooner. I even carry a spare fuel filter under the back seat in case I need to change one out on the road.

Jim W.

 

[ABennin]

Battery cables are tight and grounds are clean? I had a problem with this a while back. The outside of the battery grounds looked good but the inside of the ground and battery stud where nasty. I started the truck one morning and it ran like crap and died.

 

[Alan Reagan]

Make sure the drain valve on your filter is closed all the way.

Usually when a Cummins lopes, it is getting air in the system. If you took the top off the fuel filter and then put it back without replacing the o ring, you may be getting some air. Also check all your fuel lines and make sure you don't see any fuel weeping. Usually you will get whiffs of raw diesel in the engine compartment if this is the case. Feel around the top of the fuel filter for weeping fuel as well.

Then move to the throttle body. Could be getting air thru or the throttle body may be defective.

 

[LILHauler]

I ran into this after my truck sat a week. First thing I did was put some Diesel fuel conditioner in the tank. It cleared up the rough idle right away.
I must have fueled up shortly after the station tanks were filled. This can stir up any water in the main storage tank and this can be transferred to the tank your filling.