Thanks for the advice. I'll do that.

 

My scanner can show fuel trim and O2 sensor voltage levels - what O2 sensor values should I be looking for that might indicate a degraded O2 sensor? 96,000 miles on the clock.

I was running 7-10% rich on LTFT, after a valve adjustment I'm getting 0-2% rich. My gas mileage isn't great (18mpg average, city, top down, A/C, hilly driving) but it isn't terrible either (eeked out 28mpg averaging 75mph on a road trip, top up, A/C on).

 

I'm surprised nobody has asked this (unless I missed it) but.... what 'bad' mileage are we talking about here?? And how do you drive your car, and what elevation/octane?

 

What $200 sensor? Just get the $90 denso one from rock auto, works like a charm.

 

19 isn't that bad. City driving semi-aggressive that would be normal. I have seen 16 miles per gallon consistently if I beat the crap out of the car and I average about 24 right now

 

www.oxygensensors.com

 

You missed it. The third post (OP response to first question asked).

Is it laziness to actually read even a few posts down, or is it poor reading comprehension? Whatever it is it seems to be all too common.

 

Couldn't hurt to run a bottle of Chevron Techron through the tank before spending more money on an O2 sensor.

 

Chevron Techron Concentrate Plus has increased my gas mileage by about 1-2 mpg on multiple cars, s2000 included.

have you checked your tire pressure and alignment?

 

I took some snapshots of my primary O2 sensor readings while idling, trying to catch 30 sec increments. The second one looks a little wonky, and everything I'm reading says there should be one cross-count per second. Replace?