Am having a bit of fun with the ex trog toyota corolla. It is a VVTI 1.4 UK built corolla GS. The tick over sits high so looking to replace the IACV (Idle Air Control Valve) Now the fun starts, I can't get the screws to come out. Have tried vessel JIS screwdrivers and a philips screwdriver and all I have managed to do is slightly turn two of the four screws. So what would you do to get the screws out as they have been there for 25 years so need a bit of persuation to remove.
So what would you do next to try and get the screws out. I'm thinking impact driver, or should I use some cold or heat before hand. Leave in the frezzer for a few days. Maybe better to drill a hole in the center of the fucked screws and hammer in a torx bit and then the impact driver. Or what would you recomend.

This is a picture of the throttle body

This is the parts diagram and the IACV is 22270
https://www.autozone.com/fuel-delivery/ ... 331333_0_0 follow the link and picture three is of the screws in question
