Vibration at high idle

[liberty]

I looked around on previous posts but I couldnt find this specific problem.

In could weather my 04 automatically idles up to 1000rpm to help keep the engine warm, once it idles up I get an erratic vibration, It doesent seem like a rough idle because you cant hear any difference in the sound of the engine and the rpm doesnt fluctuate. The entire cab of the truck shakes quite noticably when this happens and its not a constant vibration, theres about a 1 or 2 second lapse between vibrations.

The funny thing is when I use my cruise to idle the truck up it idles at 1100rpm and the vibration is completly gone.

Its also not there at low/normal idle.

Any ideas or help is appreciated.

Dallas

 

[betterthanstock]

It tells you (or in my 03 it did) in the owner's manual that it will idle on only 2 or 3 cyliders at a time, to keep the engine warm in cold weather.

 

[DPKetchum]

Mine does it auto high idle and runs smooth when in the teens. Sure you don't have something loose or touching under the hood. Thought the cylinder delete to aid in warmup was a 2nd generation thing. Never have read a post about a 3rd generation doing a cylinder cancel in cold temps.

 

[liberty]

Yeah, Im not really worried about it, I just wanted to know what was causing it. The best way I can describe it is a pulsing vibration and it only occurs at 1000rpm on the auto high idle.

thanks anyway guys

 

[JHardwick]

Mine has done this since new in Feb of '03.