My girlfriends 01 Mitsubishi Eclipse GT (3.0L) is acting up. It is happening when the car is first started after sitting for over a few hours. If you try and use the heater/ac/defrosters the car's idle will loop. It will loop from normal 1000 idle down to 500ish back and forth every second or so. If you try and put it in gear it sometimes will stall on you. If you turn the climate control off though the car is fine. Also, once the car has warmed up, say 1 minute, the car is fine. I've posted in 2 different eclipse forums and they couldn't give me an answer, so I figured I'd try my luck w/ some smart people. My g/f needs to be able to heat up her car in the winter. I know that when the engine is cold it will run (rich or lean?I can't remember) to warm the engine faster. I think it has to do w/ this. What controlles this? Any idea will help. I'm going to go to Autozone to check the SES light. But that's been on for a while w/o any problems, so I think it has something to do w/ the CAI. Thanks.

I know this isn't super helpful, but tell her to sell it. That issue costs more to diagnose than to fix, I'm sure. I had an 01 eclipse...nothing but issues with that car...

^^^ Its COLD....Its amazing that it runs at all...I hate to sound like the old man here, but 20 years ago you actually had to do something called "warming a car up". The usage of fuel injection will really let you get away with alot these days.
Try hoping in an 82 mustang and pulling out of the driveway AT ALL before 2-3 minutes of warm up time (you better be good on a clutch, and lucky)

The car is compensating for the extra load of the AC being on ( the defroster is on, right?) and its keeping it running, but just barely.

If it really does warm up and run fine in 1 minute, just learn to take 1 minute before you drive away...Us "old" guys used to start our cars in the winter and then come back in the house to finish getting dressed while the car warmed up ( for 5-10 minutes)....

Its several possible things. I would get the code read and see what that is. It could be the coolant temp sensor doing it. Has it always done this or just recently. Personally, you could spend alot of time on this; I say just give the car a chance to warm up.

Dirty MAF? Maybe the O2 sensor as well? Could also be a bad PCM. I had a similar problem on a 97 gs-t, 'til I did the swap...

My truck did the same thing and it ended up being a vacuum hose being loose, I guess it was an important one too, because my idle sucked especially with the air on.

Thanks for the quick replies. The car was doing this during the 95degree summer also. Not just recently. If you turned the ac on after startup it would do the same exact thing. She's been dealing w/ it for a while, but now that winter is coming she wants it to not stall while it's warming up. I'm going to put the stock air intake back on, just to see if that fixes anything, although the CAI worked fine for over a year. Then I'll take it up to autozone.

With the intake, check all the vacuum hoses and make sure they are on, and have no holes from rubbing....I thought it was only doing this on cold mornings, if its all the time, I"ll bet its a vac. leak.

^^Most likely...

i think my cousin's b/f had the same problem on his eclipse. ill txt him and let you know what he did. he had the same exact problem of the idle looping

Well, I figured it out. This all started after I changed the plugs and wires on the car. You have to take the intake plenum off and all that good stuff. I didn't note this because I was 99.9999999999999999999% positive of my work on the plugs and wires and all the gaskets and vacuums. The one other thing I changed was the car had an ebay CAI w/ AEM filter, similiar to my setup. No problem w/ the intake at all. Except that the intake had the MAF positioned on a down tube, which I didn't like since all the brand name ones put the MAF right before the down bend. So I cut the tube added a coupler and put it where the brand names do. I guess the car didn't like that. (Yes ECU was reset after) So stock intake is back on. Cars a little slower and quiter, but 210hp is enough.

Thanks for all your guy's help.