Code P0102

I have a P0102 DTC code on my 1999 LS1 engine which is showing symptoms I have not been able to find in any other P0102 thread or documentation anywhere in my hours of research.

I've been through the P0102 troubleshooting in the 1999 F-Body Service Manual. Those troubleshooting steps have gathered a lot of information, but lead to no solution.
The engine is a used 1999 LS1. It's prior history is unknown. It was just recently swapped into my 1981 Trans-Am and has had this code since initial start up.
The harness and PCM were purchased as a package from Swap Specialties. Both appear to be a 2003+(GRN/BLU) pair set up for DBC throttle body (as desired/required).

I'll try to list everything I've tested and tried. But, I'll start with the strangest symptom:

When MAF Gr/Se is observed via PID's with my simple scan tool, it shows 2.32 g/s...Constantly. At idle or part throttle (no WOT observations were made) AND also w/engine running and the MAF unplugged the reading from the scan tool still shows 2.32 Gr/Se. Engine off, key on the MAF Gr/Se shows 0.

MAF sensor connector shows 5v on yellow signal wire(when unplugged), 12 on the Pink + wire, and the ground checked out okay using digital multi meter.
Engine off, Key 'on, MAF plugged in, the MAF Signal wire shows around .400 volts and 100hz.
Engine running, MAF Frequency(Hz-kH) and voltage vary with throttle position, as expected. Frequency increases to 3-4 kHz(3000-4000Hz) at part throttle.
I've checked the frequency and voltage both at the MAF connector and pin 31 at the PCM harness. The same expected voltage/frequency changes on the signal wire show at both ends of the wire (MAF connector and pin 31 of the PCM.

I've observed the same P0102 and 'stuck' 2.32 g/s reading with multiple MAF sensors and two different PCM's programmed by two different sources. (The Harness/PCM retailer, and a second PCM flashed with a known working 'tune' by an acquaintance).

Aside from swapping those parts(which I happened to have on-hand), and testing the individual wires with my DMM, I've also:

- Verified the pins at the MAF connector against the Service Manual
- Verified the MAF sensor wire is going to the correct pin at the PCM (pin 31)
- Continuity test in Ohms via DMM shows '0' resistance between MAF connector and PIN 31. (Both back pinned and checked from PCM side of connector)
- Used a different, old MAF connector to wire the MAF separately (puling power and ground from another source AND replacing the Frequency/signal wire at pin 31 with my 'new' separate wire. No change in symptoms.
- Engine seems to run 'OK' with MAF connected or disconnected. (No change in idle, only tested in garage). I presume this is because its running off MAP readings because the PCM thinks the MAF signal is bad.
- There are no other codes.
Readings from other sensors (o2, MAP, IAT) appear to be accurate as presented in the scan tool PID's.

I think that knowing where the 2.32 g/s value is originating or how/why the computer is coming up with this constant MAF g/s reading might be the key to finding the cause.

It's almost as if the computer is just completely ignoring the MAF sensor and the 2.32 number I see is just some default value? The Service Manual says the DTC is set when MAF Hz show as 1 second. But, my DMM shows a lowest reading of 100hz (Engine off, key On). Could there be a set of conditions where the PCM is just 'ignoring' what it see's on the signal wire? In a manner where the MAF Gr/Se would just show on a scanner with some 'default' value?

For more detail on my car and/or insight into the history/series of events leading me here, you can check out the last page of my build thread at:
http://transamcountry.com/community/...?topic=69897.0

Thanks in advance for your consideration! I'd appreciate any thoughts or suggestions.

-Tom
King of Prussia, PA