High idle when driving?

[TylerMartin]

I did a search for an answer to this problem but I could only find threads related to rough idling and/or surging issues.



With the colder weather now, my truck's high idle has been coming on like it always has in the past. Lately, after sitting at normal idle, I will take off driving and come to a stop (with clutch in and foot on the brake) and my engine will stay idling at just over 1000 RPM. It's a fairly smooth idle (no knocking or misses) but the only way that I can get it to idle back down (to 750 RPM) is by pushing on the brake hard (and I mean HARD!) or putting it in a higher gear and slowly letting out the clutch. After I do that, it idles normal until I take off and come to another stop. I've let it sit there for over 10 minutes after coming to a stop to see if it will idle down on it's own but it doesn't. The automatic high idle function (as stated above) still works perfectly and just a tap on the brake settles it back down.



I hardly ever have my Quad Box turned on and this high idle happens even when it's turned off. Just to be sure, I removed the box and wiring entirely to see if it would do it stock. It does.



What would cause this? I need a few suggestions so that I can try and fix it. It has been doing it for the last two weeks now (with the Quad Box still removed) and I'm worried that it could be damaging something. Although, the trucks performance and fuel consumption still seem to be normal. No smoke or anything either.



Thanks in advance.



Tyler

 

[RMalone]

Wow I didn't realize the manual transmission could be set up for high idle. I'm not sure but I don't see any way that the condition could hurt the truck. What does the ******* have to say about it or are you like me and avoid 'em at all costs?

 

[DPKetchum]

The AUTO high idle which all the 03 amd up have is suppose to drop to normal idle if moving or if brake pushed etc. Mine does.

 

[TylerMartin]

The regular automatic high idle function (not controllable by the cruise control) still operates normally. It idles up and down with no problems and can easily be cancelled by a tap on the brake. This abnormal high idling happens during normal stop and go driving. I really have to mash the brake pedal or try and stall the engine in order for it to drop back down to 750 RPM.



Could it possibly be the Intake Air Temperature sensor or the EFC Actuator (a common problem for those trucks with surging or rough idling)?



I'm 100's of miles away from a dealer so I won't be able to get it checked out for a while. I just thought there may have been some of you that had similar symptoms.



Tyler

 

[Smokin Dodge]

Tyler, My 03 has been doing the same thing not all the time but it does happen often just like you say come to a stop and it stays at 1000 rpm. I dont have any Idea what causes it.

 

[DIESELMAN]

My early '03 had a recall for re-flash where the Cruise Control occasionally did not release when you pressed the brake, (after running for a while) very disconcerting, it did release on pushing the clutch though.



This is just a wild thought, but is your beast up to date on its (Flash) shots?



Maybe the return valve on the CP3 doesn't release fuel pressure or sticks when returuning to idle and it runs high until pressure bleeds or burns down?



Flakey Throttle Position Sensor?



??? DM ???

 

[TylerMartin]

So I was driving home tonight for a few days off when my truck stumbled, sputtered, and died while traveling 60 miles an hour around a curve. I just about *%$! my pants when trying to steer around that corner and brake without any power assisstance. I narrowly missed a powerpole but managed to come to a stop safely in the ditch. I tried to restart it and she wouldn't go. Finally I got it started after many, many attempts, and got to where I needed to go (a few more miles). I checked the codes and the only code that came up was P0628 (power to lift pump I think). Maybe this has been the culprit of my idling problems? Anyway, I suppose that I will have to replace my lift pump now (got about 60K miles out of it).



Many of the other members weren't kidding when they said that there is no warning when your lift pump goes! I'm just glad there was no injury or damage.



Thanks.

 

[Slow Six]

I have had this exact same problem with my truck for quite some time. I finally got some time to get it in to check it out. The technician told me that a possible cause for this problem is a dirty injector. They dumped a can of cleaner in the tank and told me to drive it. There has also been an intermittent knock which he said is the same problem. I have only drove about 300 kms. since then so I have not seen much change yet. I did a search last night on engine or injector knock and it would appear that it might take a while for this to work. I bought an extra couple of cans of the cleaner and will add to more tanks of fuel as needed. When my lift pump died a year ago I got the impression that We are having more lift pump failures in Canada and especially in Alberta. I buy a lot of fuel in Alberta so I fell into that category. I needed proof of fuel filter changes to get warranty for my lift pump. From my experience on my truck I would say your idle problem is different from your lift pump. Also I was told that warranty would not cover the "special cleaner" as DC considers this as normal maintenance. I have suspicions that a lot of my problems started right from when the truck was new. The truck was a real pooch and stayed that way until the first fuel filter change. That first filter was a real mess. It took a couple of short interval changes to correct the situation.

As for this high idle situation I will have to wait and see if this cleaner works. I have just gone to a different dealership than where I bought the truck. I think the new place is a lot better but only time will tell. I want to get this fixed fairly soon as I am running out of warranty.

 

[CJEliassen]

It could possibly be a temp sensor. I had part of the fan shroud come loose and wedge the fan this past summer. I stopped at a stopp light and noticed my idle was at 1,000 RPM. I looked at the temp gauge and it was way high. It wouldn't drop down from pushing the brake, although I didn't push it real hard. Once I accelerated, it would idle normally, but when I stopped and the temps started driving up, the idle would jump up to 1000 again. I stopped and check under the hood and noticed my fan wasn't spinning. I pulled the shroud out and it was fine after that. If your temp sensor is bad, the engine might think it is overheating.

 

[TylerMartin]

Slow six,



Do you do your own maintenance? I do all my own maintenance (oil,lube, filter changes, tire rotation, etc) but today the dealer asked me to prove my fuel filter change intervals in order to warranty my new lift pump conversion. I change my fuel filter religiously every 5 to 6k kilometers due to the poor fuel that is common in northern Alberta. I have all my receipts and a mileage log (that indicates oil and filter change dates and mileage) but other than that, I don't have any more "proof". How did you prove your filter change intervals? Thanks.



CJ,



That's a good point. I let the dealer know about it (the high idling) when I took my truck in today for the new lift pump conversion. They said that if they can reproduce the issue (which I'm positive they can), they will try and fix it. They said they have seen this idling behavior before and the cause was the fuel system/pressure (ie. Lift pump). I guess I'll wait and see but thanks for the tip.





Has anybody installed a Stanadyne auxiliary pump on their fuel system to help ease the load on the lift pump? I have one with a mounting bracket for my 03 but I am wondering if it is worth installing now that I will have the new "in-tank" lift pump conversion. The guy that gave it to me said that it is quite a bit quieter than the FASS and provides 13+ Psi of fuel pressure when utilized with the stock lift pump. Any thoughts?

 

[Subby]

My 03 6speed has been doing the high idle coming to a stop thing for about two weeks now. Haven't noticed my overhead doing anything funky but don't know exactly how that system works. I can't imagine the lift pump having anything to do with this since a good tap on the brake will cancel the high idle. Just wondering if anyone has figured this one out yet.



TylerMartin?



Thanks

 

[TylerMartin]

I had the lift pump conversion done on my truck and the high idle (while driving) was gone. I'm not sure if the lift pump had anything to do with it.



I traded the truck off for an 06 megacab that seems to have it's own array of problems! I think I should have kept my 03 regardless of it's little quirks and problems. I can't afford to maintain the 10 MPG and weird pinging (from 1500 to 2000 RPM) in my new 06.



Tyler

 

[TJarecke]

Bring this to the top.

My brother bought an 03 and is having this issue.

Is there any new info on this?

 

[GaryOwen]

Had the same high idle problem with my early 03 until I installed my SmartyJr. Has worked perfectly every since! Haven't put it back to stock setting yet to see if the problem returns. Not sure why this made a difference, but maybe a reflash would have the same effect.



Gary

 

[rbattelle]

This kind of thing has been reported before.

Link 1.

Link 2.

Link 3.

Not many answers, though. Faulty water temperature sensor sounds plausible, but if that were the case the gauge would read very high.

Ryan

 

[DE Jeeper]

Not much to add, but my truck does the same thing when I turn off the Jake. With the Jake on it drags down the rpms to 700. My local dealer looked at it and said "that's weird" and that is it. They could not find any diagnostic things wrong, so I am going ot live with it. It was doing it before and after the Flux injectors so I doubt an injector issue is a cause.



Aaron

 

[stick]

My truck has gotten into this habit lately. With all the guesses of what might be the problem, the one thing that has me stumped is the fact you can push the brake real hard and it drops the idle to normal. This suggest to me it might not be a lift pump problem, or a connector pin on the ECM.



Stick

 

[DPKetchum]

Instead of saying thats weird the DEALER could at least call STAR and ask engineering to their thoughts of why its doing that. But I guess using the tools and resources at hand are difficult.

 

[jman]

It looks like this issue is more wide spread than I thought. Mine has been doing this for 30K miles now. I don't have a clue what it is, but it would be nice to fix. More of an annoyance than anything. The dealer I took mine to said "Operating as designed at this time". Don't worry about it fella's. This is how they are designed!!! HAA!!!

 

[daytripper63]

Could it possibly be the Intake Air Temperature sensor or the EFC Actuator (a common problem for those trucks with surging or rough idling)?

Tyler

O. K. my truck just developed a "rougher than stock" idle and it idles down to 1000 or so rpm and sometimes it will go down to 750 on its own and then sometimes I have to let the clutch out while in gear to get the idle to come down.

What is the EFC actuator and what does it do that can cause the above problem and does anyone else have any ideas.

P. S. I just installed a new clutch before the truck started doing this but I dont see how there can be any relation.