The year, make, model and engine size would help us answer that one for you.
van gogh was poor.
On the contrary - he was poor and unknown.
Contact any auction company, e.g. Sotheby's or Christies. If you have a genuine van Gogh you are going to be rich.
A leaking fuel injector can cause a rich condition on one bank of the engine.
Definitely not rich, but not extremely poor.
We need to know the year, make and engine to help you.
Defective oxygen sensor, the check engine light should be in your face if it is running rich (black smoke).
It will be smoking black out of the exhaust / Running RICH. Spark plugs will be fouled out/ Black. Replace them if it is running rich. Plugs will not fix your problem. Replace map sensor.
Adjust the fuel/air mixture, ensure you have an unclogged air filter/air cleaner.
I will fix it
You may have a bad catalytic converter. This may also be caused by an engine running rich which is a number of possibilities.
If the fuel is running too rich in a car, it would be a good idea to adjust the EFI or Electronic Fuel Injector (carburetor). It would also be a good idea to make sure that all of the air cleaners and oxygen sensors are clean and functioning properly.
Your civic could be running too rich because you used bad gasoline. It could also be running rich if a spark plug needs replaced.
van gogh was poor.
You need to make sure that the pulleys are all running in a straight line.
That is NOT a good idea and I will try to explain why. The computer has to see 195 degrees to get the proper air to fuel ratio. If it is running cooler the computer sees that and keeps the mixture Rich. While running rich you are paying $4.00 a gallon for gas. If the cooling system is the problem THEN fix it.
You can't fix it till you know what's wrong with it.