For the last 5 years I'd been running a 95 in my 96. 3 years with long tubes, heads, cam. Low miles, but with a crack in #1 exhaust port. Thus, some coolant was getting thru the driver's side. Fixed the head. Now, I've put my 96 pcm back in, and when the heated O2 monitor ran it threw code P0133. So is it just coincidence that this code was thrown when I put the 96 computer in (i.e. did the 95 not check for this?).

If coolant were killing my O2's, as they have been known to do, wouldn't they have killed the O2's outright and not just the heater portion? The O2's seem to behave normally, oscillating between rich and lean like they are supposed to do.

Problem is, I really need this monitor to run and pass - along with the catalyst efficiency, which I am still waiting for - as I have the AIR and EGR disabled on the car.

 

I had the same code and it was resolved by replacing the two front 02 sensors.