1997 mercury sable LS wont start. Fuel switch is in the right position, has spark and full of gas. The car will not start

I'm a bit confused here about what your exact problem is. Either way, if the car won't start and run, it cannot pass any drive cycle tests. ALL cars need to be driven for a period of time in order for the onboard computer to send and receive all required input and output signals to and from all the sensors in the engine management system, and usually for about 1/2 an hour or so before you can get a PASS or OK reading on the tests. As to why it won't run if that is your main problem, if you have good fuel (as in not old or laying around for awhile), and spark, you obviously will need to start tracking the input/output sensors and sending units built into the starting system, such as IAC valve, MAF sensor, Air Charge sensor etc.