Ironic timing...I'm not sure. I saw the thread on stubling idle down to 200-300 then back to 500, then sometimes up to 700. That thread helped me see it may be plugs & wires.

My deer impact only damaged the grill, so no internal or body damage -that shouldn't matter. I did get the new Magnaflow system on. All this happened within days of each other.

the biggest notice is the A/C is blowing hot humid air until you get rolling -does the A/C problem and the low idle go together???

I've cleaned the MAF, tightened everything I could from cold air kit back to exhaust manifolds...what gives?

A tune up might help the idle, what how about the A/C?

Its an 03 4x4 Yukon XL w/ 64k on it.

Help!!!

 

If the idle is low, the ac compressor won't be turning at the proper speed and that would definitely affect it's performance...also, I'm not sure if the PCM commands the ac off if the idle gets below a certain point? One other thing to check that could affect the ac performance is deer guts packed in the ac condensor....blech...

 

My 05 did that a lot. In fact sometimes I would be sitting at a stoplight and my truck would just turn off. It was relatively stock expect intake/exhaust too. Keep us posted if you figure out what it is.

 

My AC was doing the same crap. I had to raise the idle air values. If you have a cam, this may be the problem. I'm not sure if only intake/exhaust could be enough to throw it out of whack, but who knows.

 

I'm going to give it a tune up and see if its better. If not I may plug it up and check tuning. The engine is stock.

 

new MSD 8.5s went on and NGK55 plugs went in and the idle and A/C problem is gone. The install was a breeze except the passenger rearward plug -pain.