2003 HO sumbles when cold

[Foot]

I have a 2003 HO, 6 speed, 2500 that sometimes stumbles when idling (idle drops like the engine is being loaded down) with a cold engine. This happened to me three time is the past two months. My truck is stock except for an AirDog. I have not seen any codes but once the idle dropped low enough to kill the engine and the engine check light came on for a couple of hours. The check light went of by itself so I did not take it to the dealer. The problem happens so infrequently that I don't think I can take it to the dealer and say I have a problem. I only have 12K miles on the truck now and don't want to take it to the dealer if I don't have to. I live in Hawaii where the temperatures don't go below 65 degrees F so I don't think it is the grid heaters causing the idle to drop. Anyone out there ever had this problem or have some advice?

 

[rbattelle]

Have you changed the filters on the AirDog? Since that's the only aftermarket part you've got I'd start there.



You need to find out what code caused the check engine light. Codes can be read by cycling the key between "OFF" and "RUN" 3 times (holding it on "RUN" the third time.



-Ryan

 

[Foot]

I have changed the filters on the AirDog and stock fuel filter, and tried cycling the key to check for codes. I don't get any codes (00 00)? Do I need to use a DBRIII to check for engine codes? Also I also noticed that once in a great while I see a dim flash in the lower center of the dash in the vicinity of the red message light lights, could it be that my truck needs to be reprogrammed? I see a TSB to correct the problem for the other erroneous dash lights coming on.

 

[rbattelle]

Well, the truck is stumbling so that's not normal. If there's no codes displayed, then there are no other codes that would show up with a DRBIII. You've got to check the codes when the check engine light comes on next time to see if you can trap the real cause.



Since you live in Hawaii (lucky stiff), could it be the salty sea-air causing a corrosion problem on some connections (either OEM or AirDog parts)?



-Ryan

 

[Foot]

My stumbling problem has finally been fixed. The cam position sensor went bad and ECM required reprogramming. The cam position sensor is used primarily during start ups and is used as a secondary sensor after the engine is running for a while. A replacement cam position sensor was not available at the dealer but the dealer was able to reprogram my truck's ECM to work without the cam position sensor to allow me to drive the truck until the new cam position sensor came in. The fuel gauge in my truck used to work intermittently (gauge dropped to empty from 1/2 to 1/4 tank) so the dealer replaced the tank sending unit when the changed the cam position sensor.

 

[MFalkinham]

Glad to hear it is fixed. My truck has stumbled once (just last week) during the past 10k miles. It was under light acceleration from a stop and the engine was fully warmed up. It lasted about 1-2 seconds and the tach needle dropped to about 200rpms, then the rpm's recovered and the problem hasn't happened since.

I'm wondering if it was the lift pump twitching and is a sign of things to come? My truck just turned 24k miles.

 

[Foot]

Your stumbling sounds similar to the stumbling I experienced with my engine cold. You could have a cam position or crank position sensor going bad. I think there was another post reporting stumbling with a warm engine which turned out to be a bad cam or crank position sensor. My truck initially stumble once every two or three months, but it gradually got more frequent until it stumbled on every other start up. Have you tried to see if your truck has stored any codes? You can check for some codes by turning your truck key from off to run three times when shut down. My truck showed the following codes but I have no idea what they mean: P0633, P0463, P0628 and P0462.