3SGE Idle Issues on AC Options

[Kiolofunk]

As the title suggests, idle on my motor is really problematic lately (3SGE 3rd Gen installed on a 7th gen corolla) - well not all the time. Basically, what happens is when I'm stuck on traffic (I'm in the Philippines btw) and it stretches for 10 kms stop and go, max speeds at about 10 km/h on a very hot sunny day. Idle starts to bog down to 500 rpms +/- 50 and sometimes even 200 rpms. So i turn off the AC and idle normalizes to about 1000 rpms then it starts to fluctuate 800 - 1000 rpms every 5 seconds or so then idle goes back to normal after 10 minutes. Turn the AC on and run the usual traffic for another 30 minutes and on with the same problem.

What i've done so far:
Spark plugs
Ignition leads
Rotor cap

Also, i've replaced the following as it was due however, not sure if it adds up:
Coolant Temperature Sensor
Thermostat
Fuel Filter

Last weekend cleaned my IACV and took the TB apart and IACV apart. Noticed that the valve or the gate that opens/closes doesn't go smoothly and it seems that it does not fully close, there's a gap on gate about 1-2mm. Gave it a good clean and put everything back on, reset the ECU and drove about 50 kms and it was fine at first as there wasn't any traffic cause it was a weekend so gave up on it and tested it earlier when it was hot and was on my way to work and it started again!

Really need advice. By the way, i don't have any CEL (literally) - the person who installed my engine decided that CEL was just a headache so it's much better not to have it. Anyway it's a long story and I haven't seen him since and i'm dying to wire him up on my loom. It was running perfect before so i didn't bother much though i was meaning to get it sorted. I know, my bad.

Basically, it only happens on midday and I've never had this problem at night. Not sure if it's the weather here however it was working well before so might as well.

PS: Will upload pics of the IACV gate when i get the chance to open it again this weekend


Thanks 6GC!