a shadetree mechanic told me that a clot air filter can cause a misfire.is that possible.
Clogged. Yes, if the clog is bad enough. How long since you replaced yours?
Yes. I removed an air filter from my brother’s Neon that was so clogged it was causing a check engine light. A garage replaced his O2 sensors in hopes of turning out the light. When that failed he brought the car to me. New filter and the CEL was reset. No more check engine light.
I don’t know if misfire is the most correct term. In a modern fuel injected car, as you open the throttle, the clogged filter will not allow as much air into the engine as a good filter would. The computer will adjust the fuel injection so that the fuel/air ratio is correct and the engine will fire, but because there is less fuel and air in the engine, it won’t produce as much power.
Basically a clogged air filter will result in a loss of power. The more it is clogged, the more power is lost, but it won’t misfire until you get to the extreme when it won’t allow enough air into the engine for it to run.
In the days of carburetors, a clogged air filter would cause the engine to run too rich and it would misfire then.
OP, are you talking generally, or do you have a problem with your car?
If the latter, and your air filter is genuinely dirty–just replace it! It’s inexpensive, your car needs it done anyways, and it just might fix your problem. If no joy, then take it from there.