P0171 p1201,1202,1203.

[Bradleybnc]

I asked about the continuous misfire and idle problem I was having in my last thread. I cleaned the TB, intake, and vacuum ports and now the car is very drivable and runs great. Every once in a while it'll act up. The system shows lean on rear bank with misfires on 123. I did a compression check last time I posted and while I had the plugs out #123 showed to be very rich. They were soaked and black.

Compression #s were
#1 185
#2 205
#3 210
#4 200
#5 205
#6 215

What could cause this?
O2 sensors are new...

[Bradleybnc]

Could it be a defective o2 sensor?