O2 Sensor Problem?

this is a code for misfiring ( cylinder #4). you need to reset engine computer first. you can do this by removing negative cable from battery and waiting for 15 minutes. if there is save your radio code.

if it returns back, faulty cable for spark plug, old spark plugs, coil(s) may cause this. replace spark plugs first(it is the chepaest fix). mostly you can cure problem by this way. if not your oxygen sensor can cause this. you can understand this by running engine and observing how it idles and how it smells at back. if it start to idle rough and start to smell bad ad exhaust pipe. o2 sensor is gone.

you need to proceed step by step. 1 variable at a time please.

in extreme cases burned exhaust valve,or broken ECU can casue this too.(very rare)

check that the EGR valve is not sticking or has a vacuum leak. This valve will not operate until the engine is warm.

check also the engine coolant temp sensor (ECT). This sensor tells the engine computer that the engine has warmed up, so if it is faulty, it could be sending wrong information to the computer. If the sensor is disconnected, wires to it broken, or faulty in full cold mode, it will tell the computer that the engine is very cold, like -40F. The computer will schedule fuel for cold conditions. This is usually way too much fuel for a warm engine and it will rich misfire, idle rough, and be difficult to start warm.

The ECT has two wires going to it and is dedicated to sending information to the engine computer. It has nothing to do with your dash gauge that shows coolant temp. That sender has only one wire and is dedicated to the coolant temp gauge.

Have the coil or coil pack checked out..it may have faulty windings, and when it warms up from current flow it goes out.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

try coolant temperature sensor

Clean/Inspect Intake, MAF sensor, IAC valve for proper operation. Also check for vacuum leaks within the air intake hose and intake components. Hopefully this helps

It may be that the O2 sensor is faulty or contaminated. Another possibility is that after running rich for some time, the catalytic converter is slagged and no longer working properly. Have you been able to get any diagnostic codes from the car's computer? Is the check engine light on?

try a new crankshaft sensor not hard to change 2 bolts and a wire

Possible fuel delivery problem, fuel pump, fuel line, clogged fuel filter, leaking injectors or injector O-rings, faulty pressure regulator etc. Check your fuel pressure.

Replace the coil pack.

Replace the coil pack..