Wideband jumping from lean to rich, any explanations?
 

Just replaced my old o2 sensor with a new one (aem uego with oem new sensor) and the wideband is jumping all over the place. Old sensor was not functional but didn’t act like this.

pull the sensor and wrap it in a carb cleaner or gas soaked rag. It should read full rich.

think you got another bad one, I switched to a bosch sensor iirc after getting two "AEM" ones that were crap.

What do you mean "OEM new sensor"? Do you mean one from Mazda?

Also, what model AEM? Did it come with a 4.2 or a 4.9.... well, I suppose the connectors are different.

DNM

It was a new AEM sensor, OEM might have been the wrong term sorry. AEM customer support seems to think that the issue is an exhaust leak further upstream but im fairly sure it is just a faulty sensor

Wow. I did not know that AEM was now supplying a NON-Bosch sensor with their controllers. Another reason to go with 14point7.

DNM