new to me truck and intermittent rough idle

[JonWilson]

I just bought a 2005 pickup in Texas and went down to pick it up and drive it home to Montana. When I started it in Texas it seemed to have a slight vibration or rough idle to it but it ran great off idle and my mileage coming home averaged 21. 8 hand figured. in Wyoming I stopped and fueled up and it idled great and drove another 400 miles and the roughness was back along with an occasional long crank time. I don't know much of the history of the truck but it was built June of 05 and it is a 6 speed 4x4. it is not lacking for power at all and other than the intermittent rough idle and long cranking sometimes 8-10 seconds I love this Pickup, any one out there have any Ideas as to where I should start looking.

 

[JonWilson]

addition to above ??????

The mileage on the above truck is 118000 miles and the engine hours read 3388

 

[JonWilson]

also had new filters put in before trip home sorry about forgeting to give all info

 

[Grizzly]

I'd start with the fuel system. You said that you changed the filters, I assume fuel filter included. May be injectors, or fuel pump.

 

[BHolm]

Is it a G56 trans or the NV? The dual mass flywheel on the G56 trucks can cause rough idle and longer crank times when it fails.

 

[BillGotthelf]

I would suspect injectors but find a auto parts store that sells seafoam and add two cans to a full tank. Drive it and see if it clears up. If not I would suspect 1 of the injectors has a return fuel problem.

 

[HBarlow]

My '06 with 221,000 miles has occasional intermittent rough idle. I changed the Fuel Control Actuator (FCA) and got no change.



I recently had a level 4 (qualification level recommended by sag2) certified factory trained dealership tech run the diagnostics including injector kill test and cylinder performance tests. He found NO problems. He was a knowledgeable and helpful tech and we discussed the issue at length. He said the intermittent rough idle is a common problem and he knows no cure. He said some claim improvement after rotating the injection pump drive gear 180 degrees but he was skeptical that it is a cure.



Joe Donnelly recommended I replace all six injectors. He explained that 220,000 miles is 660,000 miles for an injector due to multiple pulses per power stroke.



I believe Joe but have decided to continue running mine until an injector actually fails and gives clear symptoms. I'm not persuaded that throwing magical chemicals in the fuel tank or expensive parts at the engine will change anything.



Harvey

 

[wcjp]

Check your lift pump and this:



https://www.turbodieselregister.com...7/193482-hah-rough-idle-cured-thanks-tdr.html

 

[GaryOwen]

Don't know why, but when I got my Smarty JR my rough idle disappeared. Maybe a reflash from dealer would work.



Gary

 

[RaymondSmith]

I get a rough idle on and off too. It is not a miss though. I would describe it as a course versus smooth idle. I haven't been able to pinpoint any pattern to it either. It does seem more noticable when the A/C compressor is running though. If it gets worse or more frequent I will take it in. For now I will just drive it.

 

[JonWilson]

I just checked codes and found a p2509 could this cause the problem and yes it does have the G-56 transmission