How to maintain the gas cylinders on Avita 950?

egg smell ( rotten egg gas ) is hydrogen sulfide
if you have a salt water chlorinator , check the operation for failure
call in a qualified pool maintainer for a proper diagnosis and quote

There are a number of possibilities here. Oil that is very old (high mileage) will become hydrocarbon contaminated over time. This can have a gasoline-like smell. There could be a problem with the piston rings allowing fuel the run down the cylinder walls into the crankcase. This can also occur in an engine that has a misfiring cylinder since the fuel is not being burned. Lastly, a leaky fuel injector can be flooding a cylinder, either when running, or after vehicle shutdown and before the fuel pressure bleeds off. This fuel will lay in the cylinder and eventually leaking into the crankcase, contaminating the oil.

The codes would appear to be an Oxygen Sensor
problems & Failed Converters,smell or not

Can't smell after all the expensive rare metals have burned off
from over heating for years

Need to find out why they failed

Check for cylinder misfires & fuel trim issues

Check for spark by removing the spark plug from the engine. Ground the plug on the metal of the engine. Have someone crank the engine to see if there is a spark. Also after cranking see if you smell gas at the spark plug whole. If you have a spark and smell gas the next step is a compression test. If no gas then check the fuel injector's wires and the injector.

Sounds like there is unburnt fuel. Could be a spark plug that's burnt out and therefore just flooding a cylinder. Which would push out fuel through the exhaust valve on the exhaust stroke. So once the fuel hits the inside of the exhaust manifold, it burns white, as if you're boiling it off. That one cylinder could have a damaged compression ring on the piston, so the fuel is bypassing it and going into the oil.

I would have your engine tuned up, and check the compressions on the cylinders.

first off you have to fix the misfire problem before you can do anything else,as a misfire will cause a fuel smell because you have 2 cylinders acting like a raw fuel pump ,by the fuel entering the cylinder not burning a being pumped out unburned.so you have to find out why it is your six cylinder car is only running on 4 cylinders and repair the problem.then you can go from there if you have to,also you will have to change the oil as it will have fuel in the oil which thins out the oil to a point it does not do it`s job and could ignite in the oil pan causing other problems

P0301 - Cylinder 1 Misfire Detected.

Possible Causes:
- Improper spark plug at cylinder #1
- Insufficient compression at cylinder #1
- Incorrect fuel pressure
- The injector circuit is open or shorted at cylinder #1
- Fuel injector #1 may be faulty
- Intake air leak at cylinder

Possible Solutions:
- Perform Injector Service
- Replaced Spark Plug #1
- Replaced Injector #1
- Replaced Ignition Coil #1

Being you have a heavy gas smell I would look into the injectors. If injector #1 is over producing it can cause a misfire. Test your compression and fuel pressure.

be sure to check the seal both on the cap and the door that covers the cap

The reason for smelling gas it these cylinders are flooding out....You may have foul spark plugs......Hope this helps.

check o2 sensors