Hi,
Recently purchased a 2001 LR Discovery 2 couple months ago with 110k miles. These codes showed up one morning along with a multiple misfire code, forgot the number. One morning when I started her up I noticed it had a rough idle which would indicate a misfire, keep in mind this doesnt happen all the time only about lets say 50 starts, and when the engine is cold it seems. So I replaced all the plugs and checked the wires to make sure they snaped on and so forth. I cleared the codes and they came back on, except for the multi misfire.

Now here are a few questions, The P0135 is a O2 bank 1 sensor 1 code and the P0306 is cyl 6 misfire. Could the O2 sensor code cause a misfire? I would think not since they regulate the fuel mixture mainly, or could the misfire cause the O2 sensor code? Or are they seperate issues? Also the fuel level could of been low during this time, below 1/4 tank with the light on. I just read through the forum and read about not going below 1/4 for fuel pump cool/lube. I will start today by not letting her get too low. Thanks for all the help in advance.

Yes I know I should replace the wires and possibly the coil packs, just looks like a PITA and dont want to throw money at it until I know the culprit.

 

Bump to the top, still need some answers...

 

Replace wires. Bad wires = bad spark.

 

If the OP is worried about it not working, and only has a few cylinders he's misfiring on he can buy cheapie individual wires for those cylinders as a test.

If that fixes it, get a whole set of good quality wires. Honestly, even if it doesn't fix it and you need to do the coil packs next, get a quality set of wires and replace them. Its basic maintenance.