Hello, I have a 1997 Chevy s10 4.3 vortec (x) 4x4 extended cab. I have a o2 sensor low efficiency code p0420. I replaced with a new o2 sensor and light came back on after resetting, in about 30 miles of drive time. Has anyone had this issue and resolved it? And if so, I would appreciate some feedback on where to go next. I have tried carb cleaner in the carb, and let it soak for a while, no success. I was thinking the cat, but its not losing power. It has 168,000 miles, looks like the cats been on there a while. I put some cleaner in the tank for the injectors etc. And 93 octane gas. No difference. Any help is appreciated, thanks in advance

 

probably needs a cat. don't buy a cheap one or the low cerium content will cause the p0420 dtc to reset.

 

check your fuel pressure, idel and under load...

 

p0420 and p0430 almost always end up being cats and I wouldn't recommend anything other than OEM, at that mileage I wouldn't be surprised. If you have access to a scantool you may be able to do a test drive watching 02 sensor data

 

My #1 O2 sensor code comes up,& my cat has been gutted.Is that why it comes up?Have a friend with a gutted cat but his light doesn't come up.

 

start a new thread. post the model, year, engine and the code