Bosch LSU 4.2 o2 Sensor 14 Years OLd, Can I use a LSU 4.9?

I'm getting some crazy lean readings. I want to replace the sensor that came with the PLX iMFD Sensor Module SM-AFR.

Whats the difference with the LSU 4.2 to the 4.9?

Connector not the same will not work.