2000 Ford Explorer Check Engine Light says #3 Cylinder Missing

With cyl. #3 misfire you should be getting a OBD-II code "P0303"
Remove your Maximum Air Flow (M.A.F. sensor) and clean it with Electronics or Carberator spray cleaner.

The M.A.F. is located on the black air guide plenum right after your air filter cover. See sketch below.

Make sure it is completely dry before you re-install it.
That "Should" take care of it.

Good Luck;
Rick

9 times out of 10 cleaning the MAP does the trick. Sorry it did not work for you.

Other possible P0303 Causes

A code P0303 may mean that one or more of the following has happened:
What you have already done has been eliminated from the list.

* Faulty oxygen sensor(s)
* Faulty fuel injector
* Burned exhaust valve
* Faulty catalytic converter(s)
* Poor compression
* Defective computer

I hope you can track down the problem at little expense.
Good Luck;
Rick