Trying to figure out if one of my o2 sensors is bad causing the car to run rich and the p0420 code to be on and what I have determined is the front o2 sensor in the header is fluctuating between .3 to .8 volts and the rear fluctuates between .1 to .7 volts . So is it one of the sensors is bad causing my issues or is the cat shot any help is greatly appreciated.
By the way its a 2002 with a 2.4 with pacesetter header magna-flow cat, resonator and muffler I'm thinking that the one in the header might be bad since its fluctuating but not sure.
oh yeah i also have the anti foulers on the rear o2 sensor also
It's your rear O2 sensor. Probably has something to do with the anti foulers that you mentioned.
www.gmscf.com
when testing the front sensor, it's best to frist create a vacuum leak and watch for it to drop below .2 volts. then put the vacuum line back on and inject some propane into the intake and watch for the sensor to go above .8 volts. if the cat is working and the rear sensor is good, the rear o2 should not fluctuate like you said, it should be a constant value, likely around .5 volts. if the cat is bad, the rear o2 sensor reading should follow the front o2 sensor almost exactly.
87 Firebird
All stock...........lol.
ok thanks I'll try replacing the rear o2 sensor first see if that fixes the problem
