It seems simple enough. In fact, if you’ve gone to an oil change place lately, I’m sure they tried to sell you one, even if you just put one in last week. That issue is for another article. The reason service shops push air filters is because they know that there are a lot of vehicles out there with dirty air filters. Yes, they’re also looking to increase their profit margin. As we keep emphasizing, anything that makes your engine work harder compromises fuel economy. If your engine can’t breathe, it’s not going to be very efficient. A car with a dirty air filter would be the equivalent of you putting a shop rag in your mouth and running around the block. I’d wager you’d be close to passing out by the time you got halfway. Don’t do the same thing to your engine if you want good fuel economy. Keep a clean air filter. It’s a simple, inexpensive item that can yield big results.
One thing I’ll mention here regarding changing the filter. Be sure to check for debris or obstructions when changing it. It’s not uncommon for small animals to take up residence in your vehicle, especially if you live in the country or if you have pets. I’ll get to why this is significant in a minute. I have sometimes found that the air box was filled with “stuff.” I say “stuff” because it could be any number of things. I’ve seen straw, insulation, and even pet food clogging up an air intake system. This is why I mentioned pets. Other animals than yours might have an interest in your pet’s food. Some of these animals like to store this booty in your air intake system. To them it’s a great hiding place; to you, it’s poor fuel economy or worse, depending on the level of infestation. So when changing your air filter, just put your eyes down into the air box and make sure there isn’t anything in there that could restrict airflow.