Lemsta2

I too have this issue but it doesnt stall. The rpms just drop and dont come back up. I've got a stock GSR ecu, I've replaced the throttle body, fiav and the isc so I highly doubt that these three things are faulty.

My very limited mechanical and electrical knowledge/experience assumes something has to force the throttle body to open up a little to compensate the revs when the AC is on. Only thing I can think of is the ISC - that one of the pins need to receive current when the AC is on but that wire thats suppose to be sending that current isnt actually doing so and therefore is an electrical issue...or am I just WAY off the mark here? 

Is there anything else I should be looking at?

I did look at buying just the FIAV from Amayama, but both my original TB and 2nd hand screws were stripped so I can't even take them off.

Yeah I just went the long way around to fix this problem. Eliminating one thing at a time until there was only one thing left that it could've been.

In the words of Borat - "Great Success!"

Ok after a long process of elimination I have fixed my idle issues!

I bought a 2nd hand throttle body which came with the FIAV. I cleaned it thoroughly like it was brand new. Took off my old throttle body from my car, and put the ISC and TPS onto the 2nd TB I bought. I did this because I know my ISC and TPS are working perfectly. Put the 2nd hand TB back on the car, started it up (cold start it hadn't been started since yesterday afternoon).

Now I don't know if my existing TB and FIAV just needed a good clean and would have fixed the problem but I suspect it was the FIAV on the old TB is not working properly. 

Anyways, that ends this chapter of DIY fixing for me.

BTW, before I got my 2nd hand TB from gumtree, I went to the local wreckers and to get a TR Magna one - but it didn't look like it would be a direct bolt on. Maybe the wrecker dude got the wrong one or something but it didn't look like it would fit, same with a NA CC Lancer one too.

All good, I figured it out now