O2 sensor/catalyst problems

[juddspaintballs]

this past summer i had another member here delete my rear two O2 sensors (one before and one after the cat on a 96 jimmy). he did so, and i haven't had a problem with them since he did it in june. i've also put about 10,000 miles on it since then. no problems still.

few weeks ago my gas mileage went to crap. did the usual tune up maintenance and crap to no avail. then i narrowed it down to the cat. so since my rear O2 sensors were deleted, i gutted my cat. about 600 miles later and probably about 50 starts or more, 250 miles into an 8 hour drive my "service engine soon" light comes on. i stop by an autozone and they read it as 'catalyst below threshold" or something like that. okay...whatever. go home. i get the same member to clear the code for me when i get home, and 200 miles and 8 restarts later, light comes on again. btw, it read as Bank 1 being the troubled O2 sensor, which is the driver's side on the Y pipe.

today i swapped one of my rear sensors into the troubled sensor's location in hopes its just a bad O2 sensor. the mechanic i work with plugged me in and read my code. I THINK it was P0420. he said that his lil tool thing was telling him that there was a problem because my front O2 sensors weren't getting a lowered reading from the rear sensors or something like that.

the sensors not communicating SHOULDN'T be a problem since i drove all summer and up until now without them working and there hasn't been a problem. I even passed emissions that way.

So, if my light comes back on...do you think it's the O2 sensor? i did gut my cat, but with the rear sensors deleted from the computer...that shouldn't make a difference should it?

any help would be appreciated, i hate having the trouble light be on

[MikDee]

Quote: Originally Posted by juddspaintballs

this past summer i had another member here delete my rear two O2 sensors (one before and one after the cat on a 96 jimmy). he did so, and i haven't had a problem with them since he did it in june. i've also put about 10,000 miles on it since then. no problems still.

few weeks ago my gas mileage went to crap. did the usual tune up maintenance and crap to no avail. then i narrowed it down to the cat. so since my rear O2 sensors were deleted, i gutted my cat. about 600 miles later and probably about 50 starts or more, 250 miles into an 8 hour drive my "service engine soon" light comes on. i stop by an autozone and they read it as 'catalyst below threshold" or something like that. okay...whatever. go home. i get the same member to clear the code for me when i get home, and 200 miles and 8 restarts later, light comes on again. btw, it read as Bank 1 being the troubled O2 sensor, which is the driver's side on the Y pipe.

today i swapped one of my rear sensors into the troubled sensor's location in hopes its just a bad O2 sensor. the mechanic i work with plugged me in and read my code. I THINK it was P0420. he said that his lil tool thing was telling him that there was a problem because my front O2 sensors weren't getting a lowered reading from the rear sensors or something like that.

the sensors not communicating SHOULDN'T be a problem since i drove all summer and up until now without them working and there hasn't been a problem. I even passed emissions that way.

So, if my light comes back on...do you think it's the O2 sensor? i did gut my cat, but with the rear sensors deleted from the computer...that shouldn't make a difference should it?

any help would be appreciated, i hate having the trouble light be on

From what I found, the sensor just before the Cat helps regulate the fuel metering, I would think the truck would have poor gas milage, & low power, due to this, the one after the Cat does nothing but throw up a code.

[juddspaintballs]

well an update: the one not on the Y pipe, but just before the cat has not been deleted. and i'm getting about 20-23 MPG with plenty of power at the moment...