And there is only one oxygen sensor right? Theres no post cat O2 sensor like those in my Camaro?

In 97....you should have one after as well.

.....which you don't care about right now. It has no effect on performance and mileage, it'* only purpose is to keep an 'eye' on the efficiency of the catalytic converter.

Are there any other parameters of the engine that I should look out for? I do know that it takes a second for it to fire upon cranking it. I have started many an L36 and they fire right when the key is turned. Could something have not been built right? The engine runs fantastic, but it just gets such bad mileage.

You might want to check the FPR vacuum line for fuel in it. The fuel pressure could also be a problem. You'd also want to consider the plugs and wires.

Take a look at the long term fuel trim. See where it'* hovering.

Long term fuel trim? Is that a parameter on the scan tool?

Yes, you need a scan tool to read the fuel trim

Where should it be hovering?

Ideal would be 0.. it'* safe to say it'* not at 0 though. If it'* more than 7 thats a possible indicator of a fueling problem.

Tuffguy - Was the Case Learn procedure done?
If not would this affect the gas mileage?