When I first start my truck the idle will hunt for a bit, with the voltage dips and comes back up. Its only for a minute or so; just wondering if anyone knows what this is, or could point me in the right direction while I'm looking for the problem

 

mine does the same. the voltage drops cuz of the grid heater turning on then off. i notice an rpm change when this happens but nothing extreme like only 50-100 rpm . just enough to change the tone of the engine. how much of a idle hunt are u having?

 

It is normal as 07 said the grid heaters are cycling and the truck is going into automatic high idle. Do have the manual hi idle enabled?

 

yeah i forgot to mention as Colo stated if its real cold out the truck will start out at 1000 rpms compared to the normal. Also i notice with mine when i let it run for about 2min at the 1000 rpm the truck seems to act like its missing. Only after you step on the brake the engine goes back to a nice smooth idle. But think i read somewhere on here this process is normal

 

07,

The "missing" or "stumbling" as I call it can be attributed to the voltage fluctuations the ECM is getting from the grid heater drain.. They need an UPS system for the trucks computer

 

sounds like its normal. Another thing I learned

 

The voltage drop is due to the grid heaters. After a few cycles it will go to normal generation. High idle is normal when cold and will even occur if it's sitting idling after warm up. It's built into the computer system. It gets cold here in TN also but not as much as CO.

 

If you have the manaul high idle enabled, but it up to 1200 and it will smooth out. That factory jump to 1000 is just not smooth for one reason or another.