My 90 sedan has a continuing problem with O2 sensors. When I purchased the car, the OBD read a 2-1-2 code, so I spent the $70 or so to replace with a universal 3-wire, reconnected the battery. The happiness lasted about 5 minutes, when the check engine light came back on. Someone said it might be a bad O2 sensor, so I ponied up and bought the original bosch for $150. Replaced the new one I just installed and viola, light comes back on in about 5-minutes or so, and another 2-1-2 (bad/faulty O2).

What do I check for now? Or should I say, write a check for now?

And yes, I have the 561 ECU.

Thanks in advance,
Matt