Seems like a hell of a lot of Mitsubishi motors suffer from surging idle speeds and stalling at lights or when air con is switched on.
I have just gone through this saga and have come across a few sites with lots of info and how to test the ISC (idle speed control) motor etc. One of the diagrams show you how the damn thing actually works and photos show you where it is located.
Also says that if you do not fix the problem (ISC motor failure) it will cause unrepairable damage to your ECU!!
Definitely worth a look:
http://www.stealth316.com/2-isc-iac.htm
http://www.autocomputersupply.com/index.asp?PageAction=Custom&ID=8
http://www.nardek.com.au/testisc510-10.htm

My engine was surging up and down between 400 and 1000rpm and always stalling at lights. . . After a throttle body clean and a reco ISC, idle sits smooth and static on 800rpm, then drops to 500rpm with air con etc on, but never stalls . .

Idle speed should increase with aircon on not decrease. Also mentions this in one of the links you provided.

Regards

Idle speed should increase with aircon on not decrease. Also mentions this in one of the links you provided.

Regards
Our TR decreases with the air con on. If fact, if I have the air con on, and shift the car into reverse with the handbrake and brakes off entirely with the intention of reversing out straight away (out of the garage for instance) half the time it stalls on me, kinda annoying really.

sounds to me like way too much resistance on the aircon pully setup, check ya compressor. also check for outstanding current drop when aircon is turned on as ya might have too much current drain for alt. (not likley though)

Idle speed should increase with aircon on not decrease. Also mentions this in one of the links you provided.

Regards


Nah. . ANY load on the idling motor will cause a decrease in revs . . try grabbing hold of the timing belt and see! . . hey - just kiddin :D . Thats exactly the job of the ISC motor, it lets a little bit more air through the throttle body to compensate for extra loads like air con, power steering, dropping it into gear in an auto etc. In the diagram see how it lets some air bipass the closed throttle plate when idling.
The Fast Idle Air Valve initially lets some air flow bipass the closed throttle plate when the engine is cold, but once the coolant heats up this valve closes and ISC motor takes over to regulate rpm and stop stalling.
My fast idle air valve is stuffed - it stays closed . . which just means the motor never idles fast when I start it up when cold. Warm it up for a minute and it idles just fine . . .can't see any reason to part with $500 - $600 for my engine to idle over 1000rpm for a couple of minutes at start up. lol

have a cool new year

My car sometimes stalls when i full lock haha

My car sometimes stalls when i full lock haha

disconnect your power steering Gemini . . . that'll give ya arms like Arni. lol

A lot of stalling is due to the PCV being gunked up or partially blocked too! My TF had it, so have several others. Btw, I have 2x ISC for sale :D

My engine was surging up and down between 400 and 1000rpm and always stalling at lights. . . After a throttle body clean and a reco ISC, idle sits smooth and static on 800rpm, then drops to 500rpm with air con etc on, but never stalls . .


specs say 700 rpm with air con off and 900rpm on doesnt it ?
so thats not good
one thing fixed it doesnt stall
try resetting the timing

maybe that reco ISC isnt good or try a reset of the TPS

Also says that if you do not fix the problem (ISC motor failure) it will cause unrepairable damage to your ECU!!

Also says, if you wank too much you'll go blind... but just look at me... :D

Also says that if you do not fix the problem (ISC motor failure) it will cause unrepairable damage to your ECU!!


what a load of Sloppy Bollocks. i drove with a rooted ISC motor for 3 years no ecu damage here. Although i think it might have made my paint crack and flake off...:rant:

Also says, if you wank too much you'll go blind... but just look at me... :D

Can't see you FiReStorM . . . . Where are you . . . no, can't see You :D lol

so... my car seems to idle sometimes up at like 1600 rpm.. and then if u tap the accel it then comes down to normal... also sometimes idle speed drops from 800 where its suppose to be down to 500 and the car seems like it will stall..

how do I reset my ISC??

so... my car seems to idle sometimes up at like 1600 rpm.. and then if u tap the accel it then comes down to normal...

sounds like your throttle plate may not be returning to fully closed position . . check that it is resting on the throttle stop screw when you lift your foot slowly off the accel pedal . . . if it doesn't sit against the stop screw you may need to adjust your throttle cable (usually needs a couple of mm's free play) . . or return spring could also be a bit week, not allowing it to close completely.

Can't reset your ISC . . you can only check the motor windings for continuity and correct resistance with an ohmeter.