[chinaloy]

Duffy, what i meant to say was that just because the front sensors fail, it does not mean the rear sensors will follow in so much as if one front fails, it seems that the other front follows very shortly after.

As for the Bosch vs. NGk or Denso. I have not seen empirical evidence saying that Bosch is bad for Toyotas.

As a matter of fact, I just replaced my spark plugs with the oem Densos and my mileage went down and my truck cranks over more before it starts. My orig plugs had 135k miles on them and the gap was huge, but the truck ran better. go figure.

It's electronics, the ECU doesn't care who made them, it just reacts to them.

I have come to the fact that O2 sensors are wear items and they need to be changed periodically. I used the universals because of cost. They are easy enough to change. If I need to change them out 5000 miles earlier, then so be it, they were half the price of oems.