Several weeks ago I got the MIL light for a couple engine cycles and it then went away. Since I had been wanting to get a OBD-II code reader for a while, I took the opportunity to pick one up to check out the history and see what code had been set and stored.

The code was P0335. The procedure in AllDataDIY looks pretty straightforward {unplug harness, remove two screws, R&R sensor, etc} but the standard time for the job is 2 hours, which hints to me that it may be a bit more involved that what is shown.

My questions:

1) How difficult a job is this? Is this something a shade-tree mechanic could do along the side of the road if necessary, or do you have to pull grills, radiators, and hoses to gain access to the sensor?

2) Since the light has not come on again, but this is my only vehicle at the moment, would anyone think it wise to pick up a new sensor and keep it on the shelf in case of an eventual failure? I think I have seen the part on line for $50-100. Not unreasonable insurance if I can change it out myself.

Suggestions?