Troubleshooting an AFR gauge/sensor, l**Finally Figured out my issue** Options

[jim_hoyland]

I installed the Innovate MTX L in 2012 and it worked fine until June of the year when it would go into the E8 mode. The techs say this means a faulty sensor. I replaced it and have continued to have erratic activity.

For example: it may run in an acceptable range for a while, then suddenly go to reading either too high or too low that are unreasonable; it sometimes freezes on a reading, and at other times it goes to E8.If I turn the ignition off and restart the engine, the gauge goes to a normal reading, then goes through the same routine.
This sensor is 3 months old, car is in perfect tune.

I changed the 12v power source, used a different ground, and recalibrated several times

Anyone had experience troubleshooting these AFR's ?

UPDATE_It was caused by contamination ! I have been adding MMO to my my fuel over the past year. When I ran out of MMO, I just ran straightgas without MMO. The AFR sensor reverted to normal operation and all is good. Interesting...you'd think the MMO would burn off or dissipate by the time it reached the exaust. Now I;m wondering if the MMO caused exhaust smoke upon downhill deceleration ?