Expy Started Idling Rough Today

[Greg Conn]

My 2000 Expy with 60,000 miles started idling rough today at idle with the air conditioning on. While driving down the road, it's fine.
When I switch the air conditioner off, it idles completely smooth.
Also, the "Service Engine Soon" light is on.

I'll have to drop it off at the dealer tomorrow.
Any ideas what might be causing this, and why the idle completely smooths out when the AC is turned off?
Thanks.

Regards,
-Greg

 

[ELVATO]

If you can, try to get the codes read at Advance/Autozone. Try to get the actual code, and post it here.

How are the RPMs when it's idling rough? How are they when you turn the A/C on or off?

 

[nvycrmn]

i agree. get the codes before you take it to the dealer. we can probably get you in the right direction for a whole hell of a lot cheaper

 

[Greg Conn]

How are the RPMs when it's idling rough? How are they when you turn the A/C on or off?

It fluctuates up and down about 400 RPMs when it's idling with the AC on.
With the AC off it idles smoothly at around 800 RPMs.

Regards,
-Greg

 

[ELVATO]

Is your AC still blowing cold?

 

[Greg Conn]

Is your AC still blowing cold?

Yep, the AC works great...blows ice cold.
It's just that when it's idling with the AC on, it idles so rough that it seems as if it's going to stall any second.
It's as if when I remove the load of the air conditioner running, the idle smooths out.
And, as I said, it runs perfectly driving down the highway with the AC on.
It only gets rough at idle.

Regards,
-Greg

 

[ghettoracer]

I wonder if the clutch pack in the A/C compressor is working right, it would click on and blow cold but also can be dragging causing your truck to run rough. You might want to change it out and see if that cures your problems or spray a little WD-40 on the seam of the pulley (where the clutch meets the pulley) and see if it does it still or not, might just need to be lubricated a little to stop the dragging. If it stops dragging, then you might consider changing it out or apply white lithium grease spray where you sprayed the WD-40 but remember not to get that stuff on the pulley or the belt!

 

[mikegigabyte]

I had around 35,000 miles and mine died at a stop light, ac on full blast. It was a dirty IAC idle air control valve. New its over $100 or pop it out and spray it clean for free. Ive had to do this 2 times now and I only have 40,000 miles on a 03. Maybe its because I dont drive it enough but look into that, its right next to your throttle body I think, I think it has 2 bolts and a wire harness plug