Cardiogold

I have owned my 2003 M/T Baja since March and it has been a nightmare ever since. Not the vehicle's fault. Fast forward an engine rebuild, an idiot mechanic, 2nd blown engine, and an engine swap by another mechanic and I now have a Baja that runs great with the exception of a check engine light with a P0507 code. The idle is off and on a bit high so I plan to try to clean the IAC valve today to see if that helps. That being said, I am starting to experience shifting issues. I saw on another post that I read at one point that on manual transmissions this can also be a faulty neutral switch. Is this a possibility if cleaning the valve doesn't help? Thanks in advance. I am no expert but I love to learn.