Alright, went to get my car inspected today and the CEL kicked on during the drive there... it kinda sucks since it has been off for the last 2 weeks and 450 miles. Anyhow, the two codes I got are:

P1170
Manufacturer Control
Fuel Air Metering

P0140
O2 Sensor
CKT No Activity
(Bank 1 Sensor 2)

First Code:
I assume this is for the MAF. It's not in the intake tract, but it is plugged in. I think the ECU might actually be noticing that there is no airflow. This one did not trigger the light, but it will keep my from passing emissions. So, we'll need to revisit the OBD2 MAF bypass question from a month or so back.

Second Code:
Rear O2 heater is dead.... I think. Since it says sensor 2 that means it is the rear right? I have a new one in my garage that I'll toss in tomorrow.

If anyone can verify either of these or give suggestions for MAF bypass without tossing a code, I'm open to suggestions. MAF suggestions should be made in the original thread.

https://www.miataturbo.net/forum/showthread.php?t=14166

 

Not to hijack or anything, but I too have the P0140 CEL. I've changed the rear o2 sensor and it did nothing. Me thinks its a wiring thing