I'm all of a sudden getting 16 miles to the gallon on a 2002 Ford Focus SE dual overhead cam I was getting 25 to 30 miles per gallon

That is a big drop. Have you been keeping up with regular maintenance, spark plugs, plug wires, pcv valve, etc? Do you always use the same brand of fuel and octane? Fuel smell, possible leak?

Yes change spark plugs spark plug wires coil pack PCV valve all vacuum lines and found that one vacuum line is little tiny plastic one coming from the intake manifold to a sensor on the left side by the firewall so I changed it to a regular size vacuum hose could that be the problem

I do have a fuel smell coming out of the exhaust also

Merlin, never try to improve the engineers work, that "little tiny" vacuum line was probably designed that way for a reason, replace it with the old one or similar size and let's see what happens.