benz83

I have a 2000 ml430 suv, i was getting P0300, P0307, P0307 on my old scanner.
130,000 miles

I replaced all:
Injectors (8)
spark Plugs (16)
front cats (2)
fuel filter (1)

Bought 4 coil packs, swapped them around.

Bought more advance code reader ( matco determinator ) same as Genisys

MAF reads ok
O2 sensors
1/1------.85
1/2------.83
2/1------.88 then after a while goes to .03
2/2------.47 (never moves)

all start at .47 then rise to listed above numbers, after reaching listed above number they dont move no more than .02.

Also when i disconnected the exhaust pipe from the side of the motor after 5 minutes the misfire goes away.

Question is the front and rear O2 sensor the same or can they be replaced with the same sensors.