Replace the IAC on back of TB and clean the bore in which it installs into. And I bet the CAT and plenum are shot .

 

Replaced that front o2 with a new one, started it up and no change. Drove it for awhile and it got smoother, and within a half hour it was smooth as silk. We live right by some major highways here (rt 9) and after dinner decided to take it for a ride since it had completely cooled down, still great.

Thanks guys! Now I just need to do the exhaust, some new rear brakes, and maybe a tire or two and alignment. Front end also has some slop, but all in due time. Thanks again!

 

Did you reset the ECM after putting the new sensor in? Its not critical, but it seems like you didn't. No biggie, the more you drive the truck, the ECM will relearn that there is a new O2 sensor(usually around 200 miles).

 

Yeah it's wierd cause I drove it last nite and it was fine, now this morning I went to go to the gym and upon startup and within a few seconds, the CEL was back on and it wasn't running as well as last nite. I have to go take a ride and check out a house, so I may take the truck instead to try and log some more miles.

 

K just hopped under here, it is running better, but its still running mighty rich, and I'm running out of options. I just noticed (didn't hear it over the straight pipe) the cat is leaking air, the bottom of it appears to have split. The exhaust isn't really old or in decrepit shape, I'm wondering if the o2 being bad for so long caused the CAT to go down hill? Looks like you were onto something Zman!

 

The plenum needs to be checked, take the TB off and look down in there with a small extendable mirror and flashlight. Look all around .

 

...and the cat appears to be hollowed out. This just keeps getting better and better!

 

Will do, what telltale signs am I looking for? And if my logic is right, a hollowed cat would throw a CEL from the 2nd sensor right? Due to the non op cat not doing its job? Like I said I put the 2 new O2s in and it ran really well, CEL even went out, then yesterday morning back on and its running rich. The codes that came up now are P0171 and P0172 saying rich mixture and lean mixture. A TPS code came up too but I foolishly unplugged that when the truck was running not thinking.

 

Yes, with a hollowed out cat the downstream o2 can but not always throw a code. You can buy 2 18mm sparkplug non foulers, screw one into the bung, drill the second one out with a 1/2 inch drill bit and screw it to the sensor and install. This moves the sensor out of the flow of exhaust and fools the pcm into thinking all is good.

 

Union, I live in Jersey just like you. You will never pass inspection with no cat. Even if you fix the CEL problem. (In NJ, if you have a CEL light on at inspection= automatic fail). Remeber if they can't use the OBD II hook up, they still use the probe in the tailpipe. Also, they do the visual inspection under the truck.