Limp Mode After A Long Idle

[Roy W]

JUST AN FYI POST. Twice in my 05's 125K history it has gone into limp mode, and both times it was after a long idle period at normal engine temperature. The cause is high UNDER HOOD temperatures. The first time was when I pulled off the highway to take a cell phone call and wound up talking for 30 minutes. When I pulled back out into traffic.....Limp Mode. The second time was at the boat ramp letting the AC cool the truck off and I got to swapping lies with the guys at the boat ramp for about 30 minutes. I got in it and ....limp mode.

The interesting part is that it does not show a CEL or throw any codes. If it happens to you, do not panic, it will go away if you turn the truck off and let it sit for a while. Opening the hood helps.

[rapidoxidationman]

Anybody know what sensor makes this happen and where it is located in the engine bay?

[DmaxMaverick]

Difficult to say, absent of DTC's. My SWAG is air intake temp. This is an issue with many LLY's, and one remedy that works much of the time is an upgrade to the 2006/LBZ air intake system (airbox/plumbing).

[Kennedy]

My 2005 did this a few times early in it's life. It essentially made huge plumes of smoke and was just plain lazy in high heat and elevation. That was in the days of the Edge Juice. Since I did my own programming it did not come back. My guess is that something in the turbo control tables pushes the desired boost or vane positioning off to a bad place. I take more control of these when I reprogram and cannot recall it happening since.

IAT is sensed in the MAF sensor.

[More Power]

I would lean more toward thinking it's due to a high fuel temperature - heat soaking. Fuel temperature has been monitored since the electronic 6.5. Jim