Bogged acceleration.

Alright guys I need help I've replaced both the 02 sensor and the af sensor on an 01 per runner. The maf has been changed about 40k miles before. Same with plugs and wires. When I floor it it Boggs down. Now if it's a smooth pedal acceleration to the floor it's fine I suspect the cat? Any others with this problem? Other than that it runs fine.

 

any codes? do you have an OBDII you can hook up with live readouts? Maybe you can see some changes to the air/fuel mix or something...

 

Yes originally it flashed the codes for the o2 sensor so again replaced both of them it did ok for a day or so then started acting up again. Just today took it to a local autozone had them read the codes same thing. I dont have an obd reader but that's what I've been seeing from those I've borrowed/ used. I'm leaning towards the cat for the fact that under a start its bogged, on highway I can floor it and the thing flys. Also the shifts seem a little off I'm baffled

 

Also why I'm leaning towards the cat, from what I've read on previous threads a bad one will make the o2 sensor codes appear

 

Did autozone tell you the exact codes, or did they just say "it's your O2 sensors"?

Yeah, that's interesting. A bad cat isn't necessarily going to cause it to run like crap, unless maybe it's really clogged. That's just for emissions. A bad upstream O2 censor could effect how it runs, but the rear O2 censor is just to make sure the cat is doing its job.

What brand O2 sensors did you get? I've heard (though not personally experienced) some store brand O2 sensors are crap. OEM are best...

 

Off brand unfortunately, just a 2 pack from Amazon. Autozone showed the code p0420 I think is what it was I didnt grab the print out but that was the only code shown. It is 18 years old so It may be time to replace it or just straight pipe it. It's just strange that it did ok for a day or so then it runs like this now. And the tps and maf are some what newer.

 

Does the truck start nicely when the engine is both cold and hot?

 

Yup fires up fine hot or cold. Maybe I haven't driven it long enough for the computer to figure it out?

 

Don’t know but maybe try a new knock sensor ( I hear they wear out and are cheap enough)

 

Wouldn't that definitely show a code?

 

Don’t know, sorry

 

P0420 is Catalyst Inefficiency. NOT o2 sensor codes. There was nothing wrong with your old o2 sensors if that's the only code that was there.

 

While you're at it try a new headlight bulb. I hear they wear out and they're cheap enough.

 

Try a new number 2 spark plug, as well

 

Ok so driving today had a backfire through the tail pipe I'm worried it may be the timing now but the timing belt was just done at 150k I'm only at 207k. I turned the overdrive off and floored it from a slow roll then it backfired.
Adding on to this I just drove maybe 30 miles at highway speeds checking after the backfire to make sure everything is still in place. I can literally grab the exhaust pipe at the end it warm not hot. Everything before is pretty hot.