Hello everyone,

I've been having an issue with my brother 1999 Honda Accord 2.3l vtec motor. I keep getting an issue with the IACV and it keeps throwing a P0505 code at me. The car would idle fine until it warmed up then it started surging in rpm. To be honest I'm all out of ideas.

Things I've done so far:
replacement the IACV and taken the plenum of to clean it alongside the throttle body.
Removed the coolant and put new coolant in
Checked for vacuum leaks (none)
reset ECU
Some other stuff I cant quite remember

A issue that I don't quite understand just yet is when I remove the connector that connects to the IACV, the rpm does not drop like the manual says when I'm trying to do the base idle. When I remove the connecter for the MAF it makes the idle better but still not adjustable. Any ideas would be very helpful to me!

Thanks.