Bad fuel related to Coronavirus ?

[oragex]

I've seen a few topics about cars having trouble starting on cold weather. I wonder if fuel quality may actually be related to some of these situations
During the pandemic, people traveled very little by car and gas stations didn't sell much gas.That also means lowered revenue for gas stations. Maybe some gas station owners were tempted to 'cheat' a little, maybe mixing some water into their tanks, or using lower quality gasoline from suppliers. Remember, at some point there was so much gas on the market, the barrel was selling at a loss.

Water in gasoline can surely cause a hard start in cold days. I noticed my car was not performing very well after fueling from my usual gas station. After the tank got low again, I went fueling at another gas station, and immediately noticed a difference in acceleration.

[abscate]

I think bad fuel is a very rare correct diagnosis. If you pump 500 ml of fuel into a jar you can see if you have a water issue of consequence.

Remember, no fuel tank shall fall below 1/4 full in winter.

[RickHaleParker]

Was the difference in acceleration measured objectively or subjectively?

Fuel is not a profit source. For most retailers fuel is a loss leader, because competition is so fierce that it retails at or below the bulk price. The only reason a retailer sells it is to get you to stop there and hopefully come in and buy something that is profitable. The profit comes from in-store sales of other items. Only a complete idiot would intentionally adulterate the fuel and risk losing customers at a time when every one is needed.

In other words adulterating fuel is financial suicide.

Freezing cold air will increase acceleration because cold air is more dense and contains more oxygen for a given volume.