you can get to the sensor by turning the front wheels full right or best yet take of the right front wheel.just ahead of the rotor you will see a small plastic panel on the wheel well.just undo the 3 plastic clips and its right there.you will have to undo the 2 plastic clipw that are attached to the brack et at bank1 coils.follow the harness up.a o2 sensor socket helps alot for this sensor

 

How much does a front 02 sensor cost?

I am getting weird timing issues with my 05 sti's idle and this might be the cause....

Any special tools to remove it and install a new one?

Thanks,
-Nigel

 

o2 sensor socket. Looks like a deep socket and has an opening along the side for the wires. You'll want to unplug the wiring harness first though so that it doesn't get too twisted up around the ratchet

 

Do some proper troubleshooting before just replacing parts, especially expensive ones. The front 02/AF sensor is around $200 so not something you want to replace on a whim. Remember that electrical parts are usually not returnable, and you definitely can't return it once it's used.
Anyway the sensor is closely monitored by the ECU, and if it were in fact defective you'd probably have a CEL with codes pointing toward the sensor.

 

i bought that sensor and it cost 200 bucks from advance with a 1 year warranty, from a suby dealer it cost 250 and no warranty except 90 days if they installed it. it takes 30 minutes from start to finish and I noticed better gas mileage and better acceleration too, I was driving around with a bad sensor for about 5 months.

 

How does one know if the sensor is bad?

You by chance didn't take pictures of the install..etc?

Thanks,
-Nigel