1992 Toyota Corolla uses too much fuel

As well got new timing belt, good timing, new plugs and wires, as well as a K&N air intake system

There could be an exhaust leak near the O2 sensor.
The throttle body was serviced as well, I am assuming. Did you replace the throttle position sensor, (TPS)? It has to be calibrated to manufacturer specs with a multi-meter as well.
Other possibilities are;
A bad ECU
Vacuum leak
Check to first items on the list and get a Haynes manual if you don't have one.
Tracking down bugs after a complete overhaul can take some time and not always be what you would expect.
Take some time to make sure everything is calibrated and break it in correctly.
Remember, a motor uses more gas when it is brand new and gas mileage will improve as the engine breaks in and things will change with time.

thanks for the quick answer as this is the first F/I I do as I have always work on carburated Toyota's. I will check the TPS as I had a feeling that might be it. I will check on the vacuum leak and the leak near the O2 sensor and let you know

I have replaced the TPS and filled up the tank will let everyone knows if that fixes the issue

Did you calibrate the TPS?

no i didn't, i need to research how to do it but i have to say i got about 5 extra miles and notice a fume smell inside the car thru the vent system telling me there is a leak somewhere i guess.

If there is an exhaust leak near the O2 sensor the ECU will think the engine is running lean and dump more gas in the motor.
The Cat could be really clogged or burnt out that the same type of thing will happen. Cats are also prone to rusting through and leaking.
Also, check the donut gasket neat the exhaust manifold/cat connection.