oxygen sensor replacement -- waaaay easier than I thought.
 

For some reason replacing my oxygen sensor seemed like a major undertaking before I just did it. it's rediculously simple, and I feel like a chump for making a big deal out of it.

Anyway, using FR Wilk's page (http://frwilk.com/early944/misc/oxygen.htm), I called NAPA, ordered a replacement sensor ($28 -- Bosch part #11027), and threw it in there. Previously it my three-wire sensor was replaced with this one-wire. From what I've read the two extra wires 'heat' the sensor to operating temp. quicker than your exhaust will.

Aaaanyway, with the new sensor my idle is steady at just under 1000 rpms, no crazy drops, studders, oil pressure weirdnesses, and it feels much much better. I'm anxious to see how my mileage will change.

So, Thanks FR Wilk for the info SmileWavy

I'm about to pick up a new o2 sensor and change mine this weekend - what size wrench is needed? I ask because i need to borrow the wrench from work as i only have up to 19mm at home.

cheers

I think it was a 21mm, but it might have been a 19. I had an assortment down there, and just felt around until I found the right one. It was pretty large though. Compare the wrench to the new sensor before you get down there... i should've done that.

22mm

AFJuvat

Thanks AFJ, that's bigger than the spanners i have, but I can borrow one from work.

Also, does anyone know whether the autothority chip (84 n/a) ignores the o2 sensor, like Wilks chip? I guess it does not since i did pass the Ca smog test with the APE chip in. I'm just trying to get a few more mpg, although with a broken odometer i don't really know what i'm getting now, just doesn't seem like many!

cheers