Rough idle?

[Infraredcalvin]

Whith the AC on my truck has a fairly inconsistent idle, I know it's prob the compressor turning on and off but it jumps around 200 to 300 rpm while sitting at a light, feels like it's running rough. The AC in my last truck (07 Tahoe) was much better and you barely felt the compressor on and off. Is anyone else having ismilar issues? I have about 4300 miles now.

[jeepsjeep]

Strong compressor means nice cool air and the engine has to work harder at idle to keep the compressor going. Take it as a good sign of a well designed and strong AC system. Your Tahoe was a GM and...well...I shouldn't rip on it. Its just....a Tahoe: soft, quiet, mushy, GM'ish. You now have a high performance muscle truck. Jeeps have always had massive AC compressors. All mine have done that.

[waumo]

Originally Posted by jeepsjeep

Strong compressor means nice cool air and the engine has to work harder at idle to keep the compressor going. Take it as a good sign of a well designed and strong AC system. Your Tahoe was a GM and...well...I shouldn't rip on it. Its just....a Tahoe: soft, quiet, mushy, GM'ish. You now have a high performance muscle truck. Jeeps have always had massive AC compressors. All mine have done that.

The AC in my 2011 GMC truck runs rings around both the Jeep and Challenger AC. The GMC cools right now, even at idle. The Chryslers AC is marginal at best and really doesn't do the job until the RPMs are up. I even insulated the AC low pressure lines which helped some, especially on the Jeep which has a lot of exposed metal tubing.

Our 6.1 Hemis idle a little rough compared to most engines. The idle also varies a bit in RPM especially when cold but 200-300 RPM variation we do not get, maybe 100 RPM at most.

[Infraredcalvin]

Thanks, this is the kind of feedback I'm looking for before taking into the dealer. This is a big engine, I'm used to higher strung pancake sixes for fun performance cars, and you're right about the gm being more cush. New stuff to get used to...

[bpjgc2012]

I notice mine idles rough at startup. It jumps slightly when I turn the ax on but can't say I've noticed continued rough idle with ac operation.

[Mongoose9400]

During initial startup the truck will idle high and bounce around as it finds it's engine idle. Normal operation. It takes time for the engine/fluids to heat up and the idle to smooth out.


Sent from my iPhone 4S

[Infraredcalvin]

Originally Posted by Mongoose9400

During initial startup the truck will idle high and bounce around as it finds it's engine idle. Normal operation. It takes time for the engine/fluids to heat up and the idle to smooth out.


Sent from my iPhone 4S

It mostly does it when well warm, which is why I thought it was a little odd.

[jyg_31]

I've noticed a vibration when idling at a stop light with the A/C on. It doesn't happen all the time but the vibration gets very loud as if something is loose somewhere and then it stops when I hit the throttle. Since it doesn't happen all the time, I know the dealer is going to tell me they can't find anything wrong, has anyone else had this issue? Any ideas on what it could be? Thanks!

[JBasco20]

mine is perfectly smooth after just a few seconds and then its smooth as silk until it sits overnight or something again..... My service manager said it was a normal characteristic of this engine..

[4Jenna]

Mine is picky at idle also. When warm and with the A/C off.

Mine usually idles around 600ish rpm which is where it is happy and smooth, other times it idles at 500rpm and the truck has a buzz/vib to it.

Pretty annoying. I usually put it in "N" and back to "D" and it goes back to the normal rpm at idle, or give it a lil throttle to get it back in its happy range.