Ok, so it was 31 degrees celius today (89 degree Farenheit). I drove my FD to get some takeaway kfc about 1kay away. Started engine cold and rev under 3000rpm till it reached normal temp. Didn't hit boost at all.

I felt hot from the sun, so I turned the a/c on. All of the sudden the RPM goes up and down during idle. Went lowest to 200 then up again,to about 1000 ,down again, up again and so on. Once I switched it off, idle went back normal.

Mods: HKS IC piping, front pipe, catback, air pods, Mine's ecu chip, running no bov and ceramic clutch. The car runs perfect w/o any problem exept it's running rich with regular backfiring.

Is there something wrong with my car?
Please help.

Yans

 

I have this same thing. There's a ton of threads on it. Search for "ISC". Could be your ISC (idle speed controller).

 

Yep, typically you need to clean the ISC. It gets built up with gunk that makes it stick, and that gives you the hunting idle - common problem. Do some searching on the topic - it's a little bit of work to get to it, as it's easiest to just pull the upper intake manifold to do it.

Dale