Wow never heard the 3 cyl. high idle before today. I have had the high idle kick in but not this. I ran outside when I heard it and thought what the heck. What I did notice is that my pyro showed 650 with the truck just idling in 3 cyl. mode. Is that right? High idle does nothing to the pyro.

 

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humm, well on my truck the high idle has kicked in, but never on just 3 cylinders

 

Well I'm hoping that's what it was. It didn't sound like anything I've heard before from my truck

 

yup, 3 cylinder drop out is VERY noisy. Sounds like the thing is coming apart.

 

3 cylinder high-idle is supposed to raise your cylinder temps faster so I'd imagine that would lead to higher EGT's.

 

That sounds about right. It is supposed to prevent "stacking". A build up on the valves and in the cylinders from running too cold at normal idle on cold days.