I had a post about my trucks idle surging with the high idle on. But my truck just started doing this last friday. I started my last friday after work to go home. After the truck started the idle started surging for 3 or 4 times then was fine. the truck drove fine the reast of the way home. I do not use the truck untill tonight. Had to go get some gas for the gen. Soposed to have a big ice storm comeing my way late tonight. So i started the truck up tonight and the idle started surging again. But this time it did it a couple of times driving down the road going less than a hundered feet. SO what do you guys think it is? I hope this edege box i have is not causeing it? it is less than a month old.I put a new fuel filter on my truck less than a 1000 miles ago. I hope everyone can understand what i am trying to say.Thanks Bobby M

 

Mine does that, as well. I notice it on the battery gauge. I feel no difference in the engine, I just see it on the gauge. After I take off down the driveway (long driveway) it levels out.

I just assumed this was normal start-up.

 

the battery guage surge and drop is the heater grid cycling on and off when it is cold outside.

 

Now I know. Thank you!

I did have a weird thing happen yesterday when I was parked and did not have the idle on. After sitting for about 5 mins (forget to turn it on), the idle jumped up to 1100 and stayed there. As if the high idle had been turned on...which it was not. It's NEVER done that before and has yet to do it again.

What in the world caused it to spike like that and remain constant?

 

Automatically does the high idle when started cold after a few min. The auto high idle deactivates if you touch the throttle or put it in gear I think.