ka24de repeated o2 sensor failure

[black240fstbak]

I have a 93 240sx with 119,000 miles. Recently going through O2 sensors in 500 to 1000 miles! Replaced MAF, injectors, fuel pump & filter, coolant temp. sensor, plugs, wires, cap and rotor. Checked timing, vac hoses. CEL comes on at idle and going down hill, closed throttle. Anyone with a solution?

[mechanicalmoron]

Check for codes.

And stop throwing parts at it.

The FSM has a procedure for checking the o2 sensor - use it.

I would think that if you have the original engine, this would have to be OBD1, but if you somehow have OBD2 (and it's O2 #2 thats going bad) with a PAIR valve, that's what actually went bad, and the cats not cooking at idle, popping the light on.

Or, maybe you have it stuck in o2 diagnostic mode, by having the screw on the ecu turned to the wrong side (vibration or whatever) and it's coming on to indicate a switch between a lean or rich condition.