I had to replace my MAF in early '08 it's a microtek, it solved the problem. it's reported a maf high signal a couple of times so I data logged 3min in park then drove a few blocks got up to 65 mph. I don't get a code but the maf is close to the 256gm/sec limit with the TPS at 2.5 volts and at idle it 12-20gm/sec. The TB is a 52mm. Any thoughts as to why? or is Tumerpro RT reading it wrong; it reads all other data accurately AFAIK.

Micro-tech MAFs are know to have some calibration issues. They tend to over-report the airflow, especially at lower temperatures.

When I ran one, I spent a fair amount of time recalibrating it to report like the Bosch MAF it replaced (using old scan data as a reference).

That's what I was attempting to do, but I somehow had the "Analog MAF in use (HLM)" option set, I unselected it and the MAF readings look normal, but when I free rev'd it to 5500 the SES lit for a split second but didn't show up in TP when I played it back.

When I try to cruise above 50 it cuts out and gets worse the faster I go and try to cruise at that speed. As long as I keep increase speed a little at a time it's OK, but as soon as I let off it starts to cut out again. This is what I was diagnosing at the time.

If this is in your '88, it will be an analog MAF. Only the TPI setups in '85 used a freq MAF.

The ECM may be in a default mode where it is creating an airflow value via n-alpha. The ECM will do this without setting the SES light or storing the code in memory.

Check at the ECM which pin the MAF signal is going to. That will verify which MAF the ECM is expecting.

RBob.

Thanks Bob.
yes, it's my '88. The MAF "C" pin is a DRK/GRN wire and is connected to B12 of the 1227165 ECM 24-pin connector. I assume this is correct for an analog MAF.
Diagram shows it to be connected this way.

So now I'm confused If I set the "Analog MAF in use (HLM)" option why does report twice the flow of when it's not set?
Is this because I'm using the '89 Corvette ARAP bin?

In $6E the "Analog MAF in use (HLM)" bit sets the NO/NC function of the 4th gear switch in the trans. The '89 MAF mask doesn't have the code to read a freq MAF. Most likely the ECM is going in & out of a default mode which is why the airflow changes.

Check the status of the 4th gear switch in the ALDL stream. Then flip the bit and recheck.

RBob.