97 astro code p0101

[bigblackcat]

About two weeks ago i had a check engine light and a low power runability concern. I went down to schucks and borrowed a obd 2 scan tool. Found to have a code #p0101 for MASS or VOLUME AIR FLOW CICUIT RANGE/ PERFOMANCE PROBLEM. I bought a reman A-1 cardone Maf sensor and installed it; cleared the code and drove with out any problems for 3 weeks. Until this week (9-4-06) When the wife was driving and barely made it home. She reported the same symptoms; lack of power under load, tranny constantly down shifting to make in up a hill. I checked the code again and found the same code of P0101. I swapped the Maf sensor with another one (parts warrenty) and cleared the code; still no change! i even swapped out this part thinking it could be bad out of the box. I cleared the code and still no change. I even unplugged the Maf sensor and the IAT sensor and no change. When I accelerate in park this is a vibrating noise coming from inside the air intake duct? Anybody out there have any ideas?

[maxwedge]

Make sure the ducting from maf to the throttle body is not cracked or leaking somewhere behind the maf.

[Supergumby]

Check your fuel pressure.
A weak pump/clogged filter can cause a MAF code and your symptoms.

[bigblackcat]

checked the voltage to the Maf (5 volts) checked the map sensor (5.05 volt unplugged) (4.85 volt plugged in; back probing) Checked the air intake sensor (5.05 volt) Checked the tps sensor (5.06 volt) tested the voltage range at the tps under accleration (.62 to 4.53 volts) checked the idle air control valve ohms (46.2 ohms) (spec is 40-80 ohms) replaced the fuel filter but have not conducted a fuel pressure test.
-what should my course of action be now?

[bigblackcat]

completed the fuel pressure test and found it to be in normal specs at 62 psi when the key is cycled. Next I unbolted the exhaust at the manifolds and low and behold; it fired off. Looks like the cat converter is plugged!!!!! Anybody knows why it would give off a p0101 code for a plugged cat converter?

[Amark89]

A wide open throttle acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 3-10 g/s at idle to 150 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.

So, in short the restricted exhaust decrease overall air flow.