Can it be bad MAF Sensor or Catalytic converter?

Hello. I have Tacoma 98 2.4L DLX. Lately I've noticed lack of power on my truck. it struggles when I accelerate, gas mileage have dropped and exhaust manifold turns glowing red after driving it around 10 miles with no weight on straight road. I pulled out cat yesterday and I could see a little light through it. like a small 1/2 inch hole light. does anyone ever had this problem or knows what it can be? any help will be appreciated. Thanks.

 

Clogged kitty, sounds like. 1/2" of flow is a little constricting.

 

should throw a P0420 engine code if the kitty needs to be shaved

 

I see what you did there.

 

there are no codes available. checked it couple times already. Maf sensor should be throwing codes as well if its faulty.
it had me change bank 1 O2 sensor couple months ago.

 

CELs and codes don't pinpoint what item is bad. It pinpoints what systems have failure(s). So just because it says bank 1 o2 sensor fail, doesn't mean the bank 1 o2 sensor has failed.

Cat shouldn't be open only 1/2 inch.

 

that makes sense. i'll change cat and see if that fixes all that. since oem maf sensor costs a thousand. Thanks for help.