Another Rough Idle Thread

[TBland]

OK, well I have looked through the archives in this forum and really am stumped with this one.



The truck:

2003 SO CTD quad cab SB, 4x4, 48RE, 125000 miles, edge J/A, AFE stage 1



I have a rough idle once the truck is warmed up, but there are NO other symptoms. Good oil samples, new FCA, smokes only under HEAVY load, very good fuel economy and power, smooth runing otherwise throughout the entire RPM range, new GDP Raptor 100 lift pump (had the problem before and after the install).



I don't want to make a $3000 assumption that this is injectors, but what else?? At idle, when I gently depress the pedal, the rough idle will clear up with very little change in RPM so perhaps this is electrical?? There seem to be no other symptoms other than the occasional common rail timing rattle at part throttle on the highway.





Thanks for any help,



Tim Oo.

 

[daytripper63]

This sounds almost exactly what my truck is doing and I almost did injectors but cant convince myself that they are the problem, plus the idle is not rough 100% of the time

 

[TBland]

Yea, mine will surprise me now and then with a smooth idle and it never does it when cold. I guess this makes 2 of us... lets see if anyone has any suggestions. The truck runs great otherwise, but I hate pulling up to the jobsite, drive thru, stoplight, etc... . it sounds like crap.



Thanks in advance



Tim

 

[CoastyAV8R]

Did you guys unplug all your boxes and try it? An intermittent problem like this would lead me to believe it's an electrical problem. If it was a mechanical, they aren't usually intermittent.

Let us know...

 

[CMChristensen]

only time mine idles rough is when has not been started if week or so or is cold out... . all three of your trucks are 03's... just a thought

 

[TBland]

I guess unplugging the boxes would be a good idea. I will have to give that a try when I get a chance. Also, the problem is temperature related, but rather than ambient air such as cold start rough running, it only does this when warmed up.



I will keep this thread open as I further research this issue as it sounds like I am not the only one.

 

[daytripper63]

I have unplugged my boxes and tried without and then tried with only edge ez box then with only TST box and then back to both boxes and have gone over wire harness with a fine tooth comb and tried injector cleaners on top of the stanadyne I have always used.