Cruiser 54, yes the throttle body was cleaned when we replaced the IAC. We are replacing the IAC again today.

CoffeeCommando, Thank you for catching the part about it happening with the AC on. I was hoping that bit of info would help narrow it down. Since it is back at my shop today they are checking the TPS too. I'll call my guy over there to check for vacuum leaks. I have them checking the AC again as well. The back story on my jeep is I've had it since 2001 at 56k, it resides in Dallas TX so it is subjected to hot dry conditions most of the time and now has 240,200 miles on it.

Thanks again for all the suggestions, if we find anything today I'll update you.

 

So where do you stand. ?

 

I have no new news, no vacuum leaks nothing. One of the guys at the shop told me that with 240K I should be lucky it still runs. The shop couldn't find anything again on Thursday. They drove it for over 60 miles and couldn't get it to die or even act weird. So I replaced the IAC, ignition coil (upon recommendation) and put in a new fuel filter. I ordered a new catalytic converter which showed up yesterday. I will do that over the weekend.
My next steps are the O2 sensors, compressor and evaporator. Nothing we've done changes the fact that it drives like a dream with no ac and terrible with the ac.

 

Ac clutch might be freezing up?

 

Don't replace the evaporator unless your A/C is leaking there. That's a big job, and not one you want to do as a shot in the dark. If it only happens when the A/C is running, I'd start looking at the compressor and its clutch.

 

No offense, but first thing you do is find a new repair shop! They replaced a pcm because of age? No indication that it was bad.

As, stated before. They are throwing parts at it, with no testing. Did they look for vacuum leaks. Did they do the simplest thing first, change plugs and wires? A bad plug wire can cause just what you are describing.

Do not let them replace expensive parts, without proof that it is bad. Sounds like they just taking you for your money!

 

I agree: check for vacuum leaks.

Replacing a PCM simply because of age? That would not give me confidence in the repair shop.

 

So, Yes we did check for vacuum leaks there are none. The PCM wasn't replaced strictly because of age. It was sending the 505 IAC code every 3 - 4 months after replacing the IAC many times and all the wiring. It is running a lot better (without AC , of course) after replacing the PCM and IAC. As far as other testing, it has all been done. Most of the repairs we do at home, it goes to the shop for diagnostic testing and AC. The shop doesn't charge me because that can't find the problem. If they do find a problem we discuss whether I'll do or they will before anything is done. Thanks for the concern, if it wasn't a family member's shop I would have gone somewhere else.

Plugs, wires, dist. cap etc were replaced less than a year ago with the first IAC because it was misfiring.

I know there is a problem with the AC clutch.I think its freezing up, but it doesn't act up at the shop. I'm planning on replacing the compressor next. The evaporator has tested fine so far so that is a last resort if necessary. I know its a huge pain.

Thanks!