Downstream PCV valve is soaked with oil,is it bad?

You have 2 of those and also 2 downstream. You have two banks of cylinders and each one has an upstream o2 sensor and it is located in the exhaust manifold for each bank. Your scan tool should say Bank 1 or Bank 2.

The downstream sensors are after the catalytic converter.

What are the symptoms of a bad upstream O2 sensor? Sensor 1 Sensor 1 is the upstream oxygen sensor. It is the sensor that measures the oxygen content in the exhaust, providing an input to the computer, which determines how to adjust the air/fuel ratio. Sensor 1 is the sensor closest to the engine. Sensor 2 is the downstream oxygen sensor.
Mar 10, 2021

Bank 1, Sensor 1? Upstream or Downstream? - Newparts.com

https://www.google.com/search?q=2015+Chevy+Impala+3.6+upstream+o2+sensor+location

The 2005 Jeep Grand Cherokee Laredo 3.7L typically has two oxygen (O2) sensors. One is located upstream (before the catalytic converter), often referred to as the pre-cat or upstream sensor, and the other is located downstream (after the catalytic converter), known as the post-cat or downstream sensor. In many cases, the upstream and downstream sensors are not the same and serve different purposes in monitoring and optimizing the air-fuel mixture and emissions.

First, check all the connectors and wiring on the O2 sensors as corrosion or a loose wire are often common causes for fault. If you have a scan tool, look at the graphing for the O2 sensors. Upstream will fluctuate while downstream is mostly steady and a dead sensor will have no display. If both are working properly then it is most likely the cat.

Personally, if I was just guessing, I'd get 1 new sensor and start with the front. Clear the codes and test drive. If the code returns then replace the upstream with the original and try the downstream and go from there. Good luck!

P0430 - Catalyst System Efficiency Below Threshold (Bank 2) Indicates Bank 2 catalyst system efficiency is below the acceptable threshold.

• Use of leaded fuel
• Damaged HO2S
• Malfunctioning ECT
• High fuel pressure
• Damaged exhaust manifold
• Damaged catalytic converter
• Oil contamination
• Cylinder misfiring
• Downstream HO2S wires improperly connected
• Damaged exhaust system pipe
• Damaged muffler/tailpipe assembly
• Retarded spark timing

Compare HO2S upstream & downstream switch rate. Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which makes the switching frequency of the downstream HO2S quite slow compared to the upstream HO2S. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal begins to switch more rapidly approaching the switching rate of the upstream HO2S. Once beyond an acceptable limit the DTC is set. Catalytic converter bad !


P0442 - EVAP Control System Leak Detected (Small Leak) The PCM monitors the complete EVAP control system for presence of a small fuel vapor leak. The system failure occurs when a fuel vapor leak from an opening as small as 1.016 mm (0.04 inch) is detected by the EVAP running loss monitor test.

• After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
• Small holes or cuts in fuel vapor hoses/tubes
• Canister vent solenoid stays partially open on closed command
• Damaged, cross-threaded or loosely installed fuel filler cap
• Loose fuel vapor hose/tube connections to EVAP system components
• EVAP system component seals leaking (EVAP canister purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve assembly)

EVAP Leaks P0442 and P0455

You did not say what your car was ,however most newer cars use 2 oxygen sensors per bank, if it is a 4 cyl replace downstream o2 sensor,if 6 or 8 cyl bank 1 sensor 2 is downstream sensor on bank that has cyl 1 on it.upstream sensor is in front of catalytic converter downstream is after the cat

shake the pcv valve up and down if the valve makes a noise its good if it doesnt repace it

See here p147 for a diagram
http://www.turboninjas.com/camry/eg1.pdf

The PCV valve and hose are on the suction (vacuum) side of the throttle, and this is meant to **** oily crankcase vapours into the inlet manifold for burning.
This should be replaced by fresh air from the upstream or atmosphere side of the throttle, the top hose in the diagram.
When the PCV valve and its hose gets blocked, and the engine is a bit worn, Combustion blow by pressure and oil vapour in the crankcase builds up and is not sucked through the PCV valve. Instead it is forced into the intake tract.
So check the PCV valve, hose, and bleed return hose to make sure they are clear OK. If the problem persists, your engine has probably developed worn piston rings, and blow by is now too high to control properly.

I hate to say this but it appears that oil is getting past your car engines piston rings or the valve seals are bad. Either one is a bit costly repair.

these engines have 1 upstream o2 sensor and 1 downstream o2 sensor..the 1 in the rear exhaust manifold is the upstream and the 1 after the converter is the downstream..make sure you replaced the right one

Likely you already know by now, that you have a broken ring or bad piston. I can't believe no one answered you!!!