of course there was a code with the O2 disconnected. I did that separately.

I ran it in diagnostic mode and could see from the flash rate of the check engine light that during heavy acceleration it was open loop anyway, and thats when the surging occurs ...sometimes.

The oil pressure gauge has started going to zero at idle..sometimes, as soon as rpms increase a couple hundred it jumps to where it needs to be, about 1/2 way to the 85 psi mark. Might stay there when go back to idle, or might drop out to zero again, Seems like something electrical affecting that too. I unplugged the sensor to check connection and it was very clean.

Im running out of ideas here. Maybe Ill buy a new coil and swap around to see if that helps. Engine coolant temp sensor too.