Funky high idle issue

Gotlift01

Gotlift01

Captain Insano
Joined
Jan 22, 2007
Messages
2,743
On my '05, whenever my high idle kicks on the truck lopes like it has a friggin cam, enough that it'll shake the truck. I didn't really notice it, besides having the slight shake, until I put my exhaust on, and now it's REALLY noticeable. It's not like a slight miss where it'll flutter a little bit here and there, it literally sounds like my GTO with a nasty cam in it. Sounds kinda cool but I know it shouldn't be doing that. Any ideas what could cause this?

I thought at first maybe it was my chip that was causing the problem, so I took it completely off and it still does it. Also every once in awhile when I start it up, it will idle a bit funky for a few seconds and then smooth out.

Any suggestions?
 
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My truck does that kinda too at startup, doesnt lope but when its cranks over it cuts out then kinda sounds like I blip the throttle a bit then it smooths out. Not sure what would cause yours to do that. How cold is it out when it does this? Video of it maybe? I'm gonna try to get a vid of what my truck does tommorow morning as its supposed to get down pretty low here tonight.
 
injector issues probably, minor though. My buddys truck started doing that and now whites smokes on start up and sounds nasty.
 
mine did that and puffed out white smoke. all i did was change my fuel filter and it stoped
 
I have to agree, it sounds injector related.
If you know someone with a DRB they can kill each injector individually.
When you kill one that makes no difference or very little in the way the truck idles, thats the culprit.

J.D.
 
aprudhomme said:
mine did that and puffed out white smoke. all i did was change my fuel filter and it stoped
Click to expand...

we had one of those instances here in town too...except the whole truck shook continuously until we swapped fuel filters
 
Well I had the oil changed yesterday and had them change the fuel filter while it was there. Only had 15k miles on that one but figured I'd give it a shot and see if that helped. Still did it this morning.

The only time it does it is when the high idle kicks up......so anything under 32* is when it happens, anything above that it idles perfectly fine.

No white smoke as of yet......well I take that back it did do it once but only once and it lasted for maybe 10-15 seconds if that.

I'll try to get some video of it tomorrow morning when I start it, that way you guys can see what I'm talking about.

I'll ask my buddy and see if he has a DRB at his shop......give that a shot and see if one is bad or not!?!

Thanks for your help guys!:thankyou2:
 
below 20*??? if it is then its your 3cyl. high Idle feature... the ECM will shut off 3 cyl. when below 20* to help warm the eng. faster...

Our trucks do it everytime its below 20*

Lavon
 
LAmiller said:
below 20*??? if it is then its your 3cyl. high Idle feature... the ECM will shut off 3 cyl. when below 20* to help warm the eng. faster...

Our trucks do it everytime its below 20*

Lavon
Click to expand...
our trucks??? dont you have a 2nd gen??

after owning a '00 for over 2 years, i could never get it to do the 3 cyl. high idle feature... then my buddy TJSHOTROD demonstrated it to me yesterday...

on the 3rd gens, the high idle is different.. the trucks do them on their own, even with the engine warmed up. ALSO (assuming you have the option turned on with a DRB) you can control the high idle yourself by pressing the cruise control button and the set button one after another, while in neutral or park, without your foot on the brake. i dont believe the 3rd gens do the 3 cyl. thingy.
 
after never being able to get my old truck to do the high idle.. im now completely fascinated by it on my new truck and i make it high idle every chance i get!! especially lately since the high temp in reno has been around 25deg for the last couple weeks!!!
 
My truck is an 01 dads is an 00 and my brothers is an 03..... both mine and Dad's have done the 3cyl. high idle since we had the smarty on and back off... my brothers 03 has done it since day one.


I sounds funny when all three trucks are sittn beside each other and we start all of them cold... it looks like they have parcisons disease.
 
The 3 cyl thing would make sense......but it doesn't do it everytime. For example, yesterday I'm sitting in line at the carwash and the temp was 28*...high idle kicked on and started idling as I described. Real rough and chopy!

Now this morning I start it, temp is 7* and the high idle kicks on and it idles nice a smooth.:bang

Doesn't the 3 cyl idle make the engine clatter a lot more? I remember watching a video after the smarty came out of one and it definetely sounded different than idling normal. The thing about mine is the motor doesn't really sound any different than normal......it just idles rough and the only place you can hear it is through the exhaust!
 
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