2000 turbo XC70 with terrible idle and dreadful gas milage

[Enid Puceflange]

Well, I changed the sensor, and the light now has stayed off for 4 days. It's a little early to declare victory but it looks really hopeful, since now the scanned O2 voltage is around 0.4v, and varies with the throttle position. MAF sensor value also changes, so I think both are now good. The average consumption right now is around 17mpg, but it's really hot right now so the A/C is on, and the journeys were all 6 miles or less.

Whoever suggested using the short Harbor Freight 3/8 offset wrench is a genius, and needs at the very least a medal and a pint.

The only hard part about the job was working out how to undo the connector - the white locking clip can be picked open with a small flatblade screwdriver, making the whole thing go really quickly. No word of a lie - from walking to the car to driving it round the block to check it was less than 40 minutes. I've done other vehicles (Volkswagen Golf, I'm talking to you) that took several hours, and required pipe wrenches and 4 foot cheater bars.

Thanks folks!