03 H.O. auto skips at idle,surges at idle

[DPKetchum]

Good friend has a bright red 2500 03 h. o. 48 re. At 130k(90%hiway/towing a cargo trailer) started surging on start and at idle. Some off idle surge low rpm. . At times feels like its missing at idle. In general does not run as it should. Change fuel filter several times and then added a BOTTLE of Howes diesel additive. Ran GREAT,surge went away etc. Now its at 135k and UNLESS he runs a quality fuel condintoner it starts doing the SAME issues. Any of several differant fuel additives takes care of the problem but LUCAS. He checked lift pump by pulling filter and timing how fast it will fill fuel cannister up. Fills it FAST under the 10 seconds or what not. But he HAS to run a FUEL CONDINTIONER or truck runs poor with surge,skip ,missing issues. ANY IDEAS?

 

[rbattelle]

Does he have a pressure box? Maybe rail pressure relief valve leaking?



-Ryan

 

[DPKetchum]

No mods. Bone stock.

 

[betterthanstock]

Maybe it's time to clean carbon from injectors.

 

[DPKetchum]

Carbon. It pulls and works every week all hiway ansd puilling a somewhat large cargo trailer. Has had can after can of diesel treat this through it . Runs fine unless you skip a treatment for a tank or tank and a half. Just started this all of a sudden. I think the fuel return valve as stated is the issue. He needs to fine a decent tech to run a few test/checks.