slowcarfast

Has anybody had a UEGO controller fail and if so what symptoms did it exhibit? I started getting AFR display dropping to 10 a few seconds after startup (similar readings in tuner studio) and I assumed the sensor was bad (the UEGO was installed by the car's previous owner). New sensor purchased and installed this weekend (I also changed the ground so it is now common with the ecu) and driving to work today it was exhibiting the same behavior. Anything else that could cause this? I know I need to get out the multimeter and test the new sensor and probably the 5v output from the controller/gauge. Any other thoughts? I should have tested it before I bought a new sensor but I do dumb things sometimes.