Service Engine Soon - 96 Chevy Truck

prolly your O2 sensor(s). I have a 96 also and I just replaced them this winter. The "book" says to replace them every 30K, yeah right. DO NOT get the "universal" style. Spend a few extra bucks and get the ones that plug right in. IIRC they were $60-65 each online. Make sure you know which plug style you are replacing. There is an in line and a four square type. Mike

I had a similar problem on a 96 Tahoe. 5.7L Engine was running rough and the MIL lamp came on. Turned out to be a bad fuel pressure regulator.

Good Luck, TJ

"cookiemonster" wrote: > 1996 Chevy Silverado, 5.7L, Service Engine Soon light came > on/off for a day or two...now is staying on. I had a local > auto parts store perform OBD check and po155 [O2 Sensor > Heater Circuit Malfunction (Bank 2 Sensor 1)] and po175 > [System too Rich (Bank 2)] codes were listed. The plugs, > wires, rotor button, rotor cap, air and fuel filters and pcv > valve have all been changed within the last 3-4 months. > > Is this a problem with the O2 sensor(s) or something with the > throttle body? Any help with diagnosis and/or solution would > most appreciated.

I replaced the forward O2 sensors on both sides. That fixed the ?service engine light?. Thanks to Mike, Shep2 and TJ for your input. However, the truck still idles a bit rough. Any ideas? Thanks again for your help! CM

yes

what part of 'HEATER CIRCUIT MALFUNCTION' is so difficult to understand ?

"cookiemonster" wrote: > 1996 Chevy Silverado, 5.7L, Service Engine Soon light came > on/off for a day or two...now is staying on. I had a local > auto parts store perform OBD check and po155 [O2 Sensor > Heater Circuit Malfunction (Bank 2 Sensor 1)] and po175 > [System too Rich (Bank 2)] codes were listed. The plugs, > wires, rotor button, rotor cap, air and fuel filters and pcv > valve have all been changed within the last 3-4 months. > > Is this a problem with the O2 sensor(s) or something with the > throttle body? Any help with diagnosis and/or solution would > most appreciated.

I thought I had it fixed.

I replaced the front (before catalytic converter) two O2 sensors since they are the only ones that influence fuel settings/flow. The engine light went off and stayed off for a couple of days. However, it was still idling a bit rough.

Engine light has come back on with code "P0175 System too Rich (Bank

CM

is it necessary that the rear o2 sensor be screwed in . I am missing the caty and muffler. will this cause the engine light to come on. All sensor have been replaced!