Hey all, I have a JDM 2003 evo 8 that I recently purchased and a problem has developed over the last week of ownership and has deteriorated.

I started having issues with my idle, it would idle really high at around 2k rpm, jump around a bit and stabilise around there. The idle sometimes would be low too.

From there, sometimes when i started the car i needed to keep my foot on the accelerator to stop it from stalling. After all this I thought it was for sure the IACV.

But it got worse, now first start of the day it starts and idles normally, but then when the engine is warm and its been driven it will refuse to start again for around 30 mins. It will crank and kind of catch but never start until a set time has passed then it will start and idle high without exception.

The other night I left the battery disconnected overnight, then cleaned the maf and iacv and for the first start of the day it idled and ran well. (sidenote i heard the rapid iacv self test clicking when it was on acc, i have never heard it before then) I then left the car and drove it again around an hour later, it started fine and idled fine.

The car also momentarily lost power while driving up a hill at around 3k rpm before regaining power after i downshifted.

The pattern seems to be if the engine is hot and there has been load on the engine and i turn it off, it will have to wait 30 mins or so for it to start and even then it will idle high.

My current thoughts are, fouled plugs, bad crank/cam angle sensor, fuel related even?

Please help this problem is ruining the car for me.