No power above 2000 rpm

[MeettheCreeper]

97 Grand am 2.4l engine no power above 2000 rpm. Hesitates to shift and if I left off accelerator it will upshift and then go to about 2000-3500rpm before becoming sluggish again.

Had codes for MAP, TPS, IAT and misfires cyl 2.

TPS is responsive according to my scanner and flows smoothly through its range from idle to WOT. IAT is reading correct. MAP changes when I snap the throttle but I did not write the change down to determine if it is reading correctly. Checked for vacuum leaks, none noted.

I think I may have a cat plugging up. I dont have a vac guage here at home to check it and I had the car running earlier so its a little too hot to remove the O2 sensor to see if that relieves any restriction.

I noted that when I pulled the air filter and drove it with the air cleaner loose it slightly improve. I was thinking I had a clogged air filter or a possible restriction in the air box. (Rodents?)

Removed the coil housing and noted some carbon tracking on it as well as carbon tracking on the number 2 spark plug. Replaced plugs, coil housing and wires(if you want to call them that).

Still have no power and no codes present or pending. LTFT is running approx. -14.5%.

I am going to run a few more test later but any input from GM techs would be helpful.

[MeettheCreeper]

Got the problem figured out. I pulled the upper O2 sensor out and drove the vehicle. Faster than trying to disconnect the exhaust system.

Got full power and it runs great.

Diagnosis-plugged Cat Converter.

I am guessing that the original owner kept driving on the misfire until the unburned fuel finally plugged the cat. I am thinking that judging by the low voltage codes for TPS, MAP and IAT that he may have disconnected them while the car was running trying to figure out the cause of failure.