High Idle Surge

[jman]

This has happened twice in about a year. It was very cold both times it has happened. Today, engine was warm because it had been driven all morning. Sitting in a parking lot and the high idle ramped it up to 1000rpm. After about 5 minutes it starts surging and the rpm was going between about 900 and 1000. Hit the brake to kill the high idle and everything was fine. It did this last year also, but it surged a few times then settled down and that was the end of it. I checked the codes on the odometer and nothing shows up.



It runs fine, mileage seems to be the same. I have 79K on it now so I have plenty of warranty left. Just thought I would throw this out and see if anyone has had this happen. I hope I'm not an "isolated case".

 

[blmyachtsales]

Mine has a surge at high idle also (does it with and without the edge). With the didgital tack on the edge I can see it is fluctuating about 40 rpm, it also will fluctuate on the highway, long flat straightaway with no throttle movement you cannot hear or feel it (the digital tack is still jumping though). Also notice the EGT's are always higher at shut down, sometimes the turbo timer keeps the truck on for a few after driving up my road (never used to do that), I have changed filters several times. Any ideas? FCA?

 

[jltcasper3]

my 05 does this also all the time when cold when it goes to high idle. It does not do it when the smarty is removed. Mine also surges up and daown id say 40 rpm.

 

[steved]

Mine was stock when it started this... about a month later I lost an injector.

It sounds like a "cammed" gasser when its sitting there... it lopes.

 

[blmyachtsales]

Steved, you're making me nervous. Any idea how I can better check for a potential injector failure. I seem to remember a thread about hearing them click or sound funny. I do have a mechanics stethoscope. Is there one or two that tend to fail more often.

 

[steved]

When it first started loping, I also acquired a bucking start... it would buck the starter, like a gasser that's out of time.

I'm not saying that's the issue at all, but its something to be prepared for...

I'm not sure if the FCA would cause this? It might be worth changing since its the cheaper option.

 

[blmyachtsales]

Yup, it does buck the starter (like it starts but then lets off then starts again). Does not do it all the time but 1 out of 5 tries maybe. I will be watching this closely and should try the fca anyway.

 

[steved]

Yup, it does buck the starter (like it starts but then lets off then starts again). Does not do it all the time but 1 out of 5 tries maybe. I will be watching this closely and should try the fca anyway.

Mine started the lope and buck at the same time (as far as I could tell)... I have some detailed thread about everything while I was in New Mexico during November 2007. You can search for it if you want.



I would definitely stay close to home... mine started while I was in New Mexico, and within a week of getting home the injector failed. Probably 4k miles total...

 

[DPashko]

Mine used to surge too. sometime it would not come off of high idle after hitting the break or putting it in gear. I had the ecm reflashed with updated software several times and it eventually quit surging.

 

[Dbonzi]

mine would surge at high idle as well

replaced the fca and it didn't fix a thing

New injectors cured the problem#@$%!

Dennis

 

[brods]

my 05 does this also all the time when cold when it goes to high idle. It does not do it when the smarty is removed. Mine also surges up and daown id say 40 rpm.

I noticed my 05 with the smarty doing that also. It only has done it when it goes to high idle on its own. Manually putting it on high idle with the cruise control it runs smooth. I assumed the lopey high idle was from the smarty giving it more fuel than the stock ECM so the rpms overshoot, the ECM corrects by reducing rpms, and the cycle repeats over and over. I sure hope thats it and its not injectors.

 

[JamesStevens]

Remember if U have the smarty and it goes to hi idle on its own it cuts out 3 cylinders to save fuel, so it is bound to idle a little rougher.

James

 

[steved]

Remember if U have the smarty and it goes to hi idle on its own it cuts out 3 cylinders to save fuel, so it is bound to idle a little rougher.

James

I believe that's a 2nd gen thing, not 3rd gen...

 

[jbucha4]

Just changed my Fca last night. It did not fix the problem. I'm not that worried about it anymore, if this leads to an injector problem then I will be in trouble

 

[MGroft]

I have an 03 how do i get the hi idle to come on. MANUALLY with the cruise control on the steering wheel??When it is about 28degrees or so it will speed up to about 900 or 1000 RPMS. This is normal.

 

[JamesStevens]

I think you need a 04. 5 or up year truck to use the cruise control for the manual hi idle, I could be wrong though

James