86MC_SS

iTrader: (3)

p0151 - O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)

p0300 - Random/Multiple Cylinder Misfire Detected

P1153 - Bank 2 Fuel Control Shifted Lean

Truck is an 02 silverado with a 5.3, only mod is catback.

My check engine light came on and I have these codes, I am using a cheesey autozone scanner to check these. I know I have to replace the driver side rear O2 sensor but what would cause the random misfire code? Would a bad O2 cause a misfire code? Keep in mind it is one of the O2's after the CAT. I replaced the plugs and wires and that did not help. I am not sure what else to check. Can someone please give me some advise?

technical

Bank 2 sensor 1 is the passenger side pre-cat O2. And yes, this sounds like it needs to be replaced.

86MC_SS

iTrader: (3)

pre-cat is the sensor before that CAT right? I replaced that O2 sensor yesterday with a new bosch O2 sensor.

technical

Yes the O2 in the pipe right before the cat. If you just replaced it, were you getting this code before you replaced it? How is the wiring... is it safe from heat? Any chance you have either a plug wire not on securely, an injector connector loose, etc...

If the O2 is good, then you have something messing up the fuel.

86MC_SS

iTrader: (3)

argh...

I checked the wiring connecter during lunch and all was good. I guess I am checking more things out tonight.

86MC_SS

iTrader: (3)

Ok after checking the wiring for the O2 sensor during lunch..and resetting the codes...the only code that pops up now is the p0300 code.

I will fiddle with it more later.

86MC_SS

iTrader: (3)

So I checked all spark plugs, wires, coil packs, and injectors. I checked for vacuum leaks and any loose connections and nothing. I used the old school water hose across the intake and vacuum source technique on different areas to check for vacuum leaks and the truck had none.

To check the coils I unplugged each plug wire from a coil one at a time while the truck was at idle and they all had spark.

To check the injectors I unplugged each injector one at aa time while the truck was running at idle and it really had no affect on the truck. It was still missing and not firing properly. Is that normal?

I am at a loss...

technical

Sounds like a rolling lean miss. Start looking at the fuel system. Check the fuel pressure first, then try some fuel injector cleaner is the pressure is good. Do you have tuning sofware? A log would be great to look at.

86MC_SS

iTrader: (3)

I dumped in some fuel injector cleaner in last night and a big can of 108 ocatane booster just for good measure [dont know why lol]. Changed nothing.

I have no tuning software. The truck is completely stock as stated before other than catback.

thanks for the help technical, i appreciate it.

I wish I could logg it no one around me has anything for an 02 silverado around here.

86MC_SS

iTrader: (3)

So my O2 sensor code came back on...

p0151 - O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)


After lots of reading and searching and gathering as much info as possible. I retraced my steps to what started all this. At first I only had one code for...

p0151 - O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)

...then I bought a new bosch O2 sensor to "fix" this problem. After replaced the bad O2 sensor with the bosch one I reset my computer and all was fine for a couple hours. The code came back on after a while and things got worse. I had more codes for...

p0300 - Random/Multiple Cylinder Misfire Detected

P1153 - Bank 2 Fuel Control Shifted Lean

....plus my O2 sensor code now as well. As you read I checked plugs and wires and everything else that would cause a random misire. Remembering that I read someone moved there post cat O2 sensors to the front of the cat , I had nothing to lose and tried it. I cleaned off my "bad" O2 sensor and stuck it after the cat...so basically I swapped O2 sensors. I reset the computer and turned the truck on and drove it for almost an hour and no more codes. The bosch sensor was junk and caused more headaches then needed. I will be buying GM O2 sensors and replacing both primary O2 sensors next week.

BOSCH SUCKS!!!

technical

WOW!!! I guess my first post was correct.

I'm just glad to hear it's fixed. And I'm not buying Bosch O2's anytime soon either.

86MC_SS

iTrader: (3)

Thanks again for tossing in your ideas and trying to help me.