I'm on my 2nd I-30. First was a 96 and I sold it at 130K mi. Ran like a top. I had to replace 2 O2 sensors in the '96. Installed they were about $250 ea (2 separate trips). Now the 'Check Engine' light is on in the '97 and according to this shop, its' the O2 sensor. Is this something I can do at home? If so, whats' the difficulty level compared to spark plugs, brake pads/rotors? I've got tools - floor jack/stands, air compressor, impacts, ratchets, etc. and want to save a few bucks and the hassle of dropping it off for 2 days... I've also heard there are 3 sensors - any way of finding out which one it is? Any help would be appreciated.

This is a DIY. First you need to get the ECU code. It'll tell you if it is the rear, right or left sensor. The ECU is located on the floorboard inbetween the drivers and passenger seat..pull off the panel to the right of the gas pedal. There should be two plastic screws that pull out. You need a flathead screwdriver. Turn the ignition key all the way on without starting the car until all the dash lights come on. Turn the screw on the ECU Clockwise until a stop(wait 2 seconds) then counter clockwise until stop. Your CEL will begin flashing. Use this to figure out what the code means: http://vbxmaxima.8m.com/ecudecoder.htmlYou're probably going to want to get some sort of penetrating oil to help break it loose. Either you can go the cleaning it with rubbing alcohol route or just replace it. You'll need to put the car on jack stands and probably some size deep socket. Once cleaned/replaced you need to reset the ECU. To reset the ECU you have to turn the ignition key until all dash lights are on, then turn the screw on the ECU clockwise(2seconds) counter-clockwise(2 seconds), clockwise(2seconds) then counter-clockwise. Start the car up and the CEL should immediately go off if there are not any other problems.