I'm a new owner with tha 2001 milly s. I bought tha car wit tha check engine lite on. Took it 2 mazda and the they told me I needed 2 coils and 2 o2 sensors. I bought 4 coils. 2 to replace and 2 back up coils. I also need to find out what the hell is the left upper 02 sensor and right upper sensor and which 1's 2 buy? I looked all over but there are so many different 1's. Can anyone help me? Even a part number may help? Also are the easy for do-it-yourself projects or just go 2 the dealer where they charge $264 plus each 4 each.

 

i have replace both upper left and rigtht. not hard to change. i got my part from rockauto.com it is cheaper. BOSCH Part # 13572 for the front, BOSCH Part # 13576 for the back, u will need a o2 sensor socket

 

So where r they exactly located? Also what r the sockets and can they be reused off the old o2 senors? Tryin 2 improve my fuel economy. Get about 150 miles 2 a tank of gas.

 

Just throwing this at ya! I get 230+ miles to my milly depending on how I'm drivin' and that's with the check engin lite on. When you say the coil, are youtalkin' aboutthe spring coils?It's been on since November! There is a "Y" shaped pipe directly under the engin. It has 2 O2 sensors before it and 2 after heading back up to engin. How many more O2 sensors are there and what does that "Y" shape pipe do? Read my previous note about my diagnostic.

 

I was actually talkin about the ignition coils on my miller cycle. Since I changed them the o2 codes went away. I still want 2 change them 2 c if my gas mileage will approve. Also 2 answer your question there r 4 o2 sensors. 2 in front and 2 in back. Don't know what the y shaped object does. Neva looked up under my car yet.