I bought my P5 new in 2001, and have kept it stock ever since. I have 128,000 miles on it.
A couple of years ago, I started getting the random misfires. Replacing spark plugs and wires helped, but it was replacing the coils that finally fixed it just about a year ago, just in time for me to pass emissions.
Shortly after that, my CEL came back on, and it was the dreaded P0421. I noticed a slight drop in MPG (about 2 MPG), but no significant change in performance, and no rotten-eggs smell.
I procrastinated, and now I have until the end of July to pass emissions again. I started searching and discovered the non-fouler trick. I have a few questions that the various threads were not clear on:
1) Will the trick work for me? I understand that it doesn't actually fix the problem, just makes me pass emissions. I'm fine with that; this car is now used primarily for commuting and I don't want to spend $1000 or so to add 2MPG.
2) I understand that there are two O2 sensors; the one at the bottom of the car near the oil pan, and one up front inside the engine. I found the bottom one. Which one would I put the non-foulers on?
3) In the main howto thread here:
http://mazdas247.com/vbb222/showthread.php?t=123634664
...it looks like it's the bottom sensor that needs to be modified. Do I need to do anything to the top sensor, as pictured here:
http://www.mazdas247.com/forum/showthread.php?t=52498
...?
4) In another thread that I now can't find, someone mentioned using a special socket or wrench to remove the O2 sensor, but didn't give any more info. What is the easiest way to remove the O2 sensor without damaging it?
I greatly appreciate this resource, thanks to all who have posted about this. I'll try to take some pictures of my own and contribute as I do this.
A couple of years ago, I started getting the random misfires. Replacing spark plugs and wires helped, but it was replacing the coils that finally fixed it just about a year ago, just in time for me to pass emissions.
Shortly after that, my CEL came back on, and it was the dreaded P0421. I noticed a slight drop in MPG (about 2 MPG), but no significant change in performance, and no rotten-eggs smell.
I procrastinated, and now I have until the end of July to pass emissions again. I started searching and discovered the non-fouler trick. I have a few questions that the various threads were not clear on:
1) Will the trick work for me? I understand that it doesn't actually fix the problem, just makes me pass emissions. I'm fine with that; this car is now used primarily for commuting and I don't want to spend $1000 or so to add 2MPG.
2) I understand that there are two O2 sensors; the one at the bottom of the car near the oil pan, and one up front inside the engine. I found the bottom one. Which one would I put the non-foulers on?
3) In the main howto thread here:
http://mazdas247.com/vbb222/showthread.php?t=123634664
...it looks like it's the bottom sensor that needs to be modified. Do I need to do anything to the top sensor, as pictured here:
http://www.mazdas247.com/forum/showthread.php?t=52498
...?
4) In another thread that I now can't find, someone mentioned using a special socket or wrench to remove the O2 sensor, but didn't give any more info. What is the easiest way to remove the O2 sensor without damaging it?
I greatly appreciate this resource, thanks to all who have posted about this. I'll try to take some pictures of my own and contribute as I do this.
