2001 3.4, no acceleration, extremely loud intake

My 01 3.4 tacoma has no get up. I looked at the spark plugs, they looked fine, a little lean if anything but nothing bad, the spark plug wires are turning a little white, but there not grounding out just yet. I just bought this truck, thought it'd be a quick fix. It's throwing the 0420 code, so I replaced the upper o2 sensor, nothing happened. Cleaned my maf sensor on my k&n filter, nothing happened. Took my front cat off, ripped apart all the fins, so now I'm straight piping. Nothing again. Is there anyway that the k&n intake is doing something to the ecu to make it restrict a lot of power? It honestly feels slower than a 22r. Where should I start now? I'm all outta money and patients, I can barely pull out in traffic. Also when I hit about 4 grand, it starts to sputter and surge. Does it sound like a poor air to fuel ratio? If so, should I find a stock intake to slap in there.

 

If it were mine, I'd get rid of the K&N (find someone gullible to sell it to), install a stock intake, and brand new OEM MAF.

Do you have COP-type ignition, or coil packs?

 

If you just got it I would do a complete tune up (Wires, plugs, oil, oil filter, fuel filter & air filter) first. Maybe try some Seafoam cleaner through the intake. Then take care of the 0420 code correctly, replace catalytic converter and see what happens. I'm sure BamaToy will chime in soon.

 

I'm gonna try borrowing my buddies intake and maf, see how see runs after that. And it's a coil pack type, but I believe they should still be good, if my intake doesn't work, I'll replace the wires. When it keeps throwing the 0420, I thought my cat was clogged but when I gutted the inside, the fins were wide open, it made no sense just because I changed the upper o2, and it still threw the 0420 after that. Thanks for the input bud