I'm still trying to figure this problem out. I cleaned all the ground wires I could find except one that's so rusty the bolt is stuck( got pb blaster on it). I also cleaned the MAF and I removed the IAC and cleaned it, I also cleaned the throttle body which was gummed up. I took it for a ride and it does run better. Smoother idle and more low RPM power, but the IMRC is still not actuating and I still have a CEL.
As far as which fuse the IMRC is I don't think it's #18. I'm pretty sure that's the heated O2 sensor fuse.