Lambda 1 vs AEM wideband

I have a lambda 1 analog input and also an aem wideband gauge. Two of them are showing different values up to 2:1 afr points sometimes. Car was tuned according to lambda 1.

As we don't know if lambda 1 is oem narrowband or wideband is there a way to justify it from ecu or somewhere? I've seen values down to 9:1 on lambda 1 if there is a max/min for a band.

If it's an oem sensor does it mean that car needs to retuned according to aem wideband? There are two censors on the pipeline. The upper is lambda 1 and the latter one is aem wideband. In ecu i was able to find just one lambda meaning that the other one is not wired to ecu.

What is the engine and vehicle, and the modifications? What do you mean Lambda 1 sensor, a narrowband sensor?

sti'06 built engine pistons, rods, etc and link ecu. by lambda 1 sensor I mean the lambda sensor that ecu uses different from aem wideband sensor. by narrowband sensor i mean if lambda sensor is oem (which i am not sure) then it would mean that it's a narrowband. but it measures down to 9:1 so i'm confused.

It's not a switching 1 volt sensor ("Narrowband") and it's not a pump current type sensor, the typical Bosch wideband. It's an earlier model of the Denso "Planar type" wideband sensor, which is accurate down to about 12.5:1 and then will skew rich. So for example, when the actual AFR is about 12.0:1 , it will read 11.5 .

Newer versions of these sensors (like on a 2015 and later WRX with FA20DIT engine) are more accurate.