And the winner is... combination wrench! I ran out and purchased a 22mm wrench on my lunch hour - my collection of tools stopped at 19mm.

Super easy job; took longer to put the car up than to change the oxygen sensor. I soaked it in PB Blaster a few days ago, it broke free with one easy pull on the wrench.

The lead from the sensor actually comes in the side of the transmission tunnel rather than the floor. Minor quibble, but it's not even necessary to pull the carpets on the passenger side if you know this. Just peel up the rearmost edge to access the blue cable that is the O2S.

I'm happy to report the m104 now runs absolutely, spectacularly well. It never surges at idle, is always smooth, and responds instantly to the throttle. Idling in park it's so smooth I cannot even tell the engine is running. Schweeet.

Now if I could just figure out how to adjust the steering gearbox without removing the intake manifold...

- JimY