Blazer just through these codes, P0135-O2 sens. B1S1 and P0306 misfire cyl. 6...

is the cyl. misfire causing the 02 code or the other way around HELP.. Truck dont seem to be missing why i am asking, could the 02 becausing the misfire..

 

what year is it and how many mile? As well as how many miles since the last tune-up(ie-plugs, wires, cap, rotor, fuel filter and air cleaner). If it were mine and it's been awhile I'd tune it up and then see. Without more info it's impossible to say 100% as you could certainly have a bad o2 sensor but with a scan tool you should be able to look at the crosscounts and come to a conclusion. Although lack of crosscounting may not necessarily point to a bad o2 sensor either. More info would be helpful. good luck jp

 

question is could the 02 sensor cause a misfire code....

or

does the misfire code cause the 02 code, since if the plug is not firing right the release of gas onto the o2 sensor throwing the code...

 

To answer your question I have seen cases of both or in other words, either can cause the other which makes it tough to tell you which way to go withourtfurther info and even then, there are no guarantees but....depending on mileage since last tune or whether you can look at o2 sensor crosscounts/info-those are important questions. good luck JP

 

I'll start with the specific meanings for the codes given as P0135 is a bit different than the OP stated:
P0135 - HO2S Heater Circuit Bank 1 Sensor 1
P0306 - Cylinder 6 Misfire Detected

B1S1 is the driver's side O2 sensor that will feed data to the PCM and affect cylinders 1, 3, & 5. Since cylinder 6 is on the opposite side of the engine, the O2 sensor would not be influencing the misfire.

P0135 is only dealing with the heater circuit. As such, it will only really influence how long it takes for the engine to get into closed loop operation. A heated O2 sensor comes to operating temperature much quicker than an unheated one.

The first thing I would do is reset the codes and see if they pop back up, especially since you are not feeling any problems. At the same time, maybe pull the #6 spark plug (passenger side rearmost cylinder) and inspect it. Also, inspect the #6 wire connection to the distributor cap. I have seen wires push off of the distributor cap slightly causing an intermittent misfire. I always use a small screw driver pushed into the wire boot as I slide it over the terminal on the distributor. This allows the air to escape as you push it on. Then just slide the screw driver out once it is seated properly.

If you do get the P0135 code back and are still not experiencing poor performance, then you can swap the sensors side to side (swap the sensors that are ahead of the 'Y' in the y-pipe). Reset the codes and drive. If the code pops back up as a P0155 (B2S1 Heater Circuit), then you know that the O2 sensor that was originally on the driver's side (now on the passenger side) is in need of replacement. If P0135 comes back even after the swap, then I would suspect a wiring issue.

As Peru stated, if you haven't done a tune up in a while, it may just be time for plugs, wires, cap and rotor.

Hope this helps!

 

thanks swartlkk

im going to try what you said and post what happens.. probably 2morrow its raining and cold in ky. thanks.