Ford Escort 1.9L code 172 O2 sensor fault/lean

[ELH]

I am trying to fix this problem
When i hook up the code read i get this code
172 R, C HEGO (HO2S) sensor fault/lean
The test is done with the engine running

The problem on the road is at stop light it will stall and stop running

On the highway it will drive with no problems

[f-superduty]

depending on what year escort you have chk the pcv valve lines and make sure
they are not rubbing through. If you have a scantool monitor pid data watching
stft short term fuel trim using carb cleaner or brake cleaner spray around intake
and gasket surfaces if there is a leak the stft will change plus or minus

[ELH]

It is a 1995 ford escort wagon
OBD I

I have all the codes fixed
The only one left is the 172 R, C HEGO (HO2S) sensor fault/lean

I have replaced the mass flow sensor
I have replaced idle solenoid valve
new fuel filter new plugs and wires
and i added injector cleaner to my fuel
I also cleaned the throttle body as well

The problem was there before i made all these fixes
and the repairs where made so i could get to this last test with engine running and thats when it gave me the 172 code