my car wont start

i have a 2001 chevy impala i changed my thermostat and throttle body gasket the car turn on right away and after about 5 or 10 min it just turned off and now wont start up again what can i do to fix this

Welcome to AF. what engine #1 and do you have spark and fuel pressure?

i have a 3.4 i have a half a tank of gas and i the car trys to turn over but just doesnt start

what is the easiest way to find out if i have spark and fuel pressure

Pull a plug wire off, insert a screwdriver into the wire end, hold the plastic handle and hold the metal end about 1/8" away from the block and have someone crank the engine, see if you have a good blue/white spark jump across the gap. If ok, spary carb cleaner or a small amount of starting fluid into the throttle body see if it kicks over.

also if you were using 7% ethonal you might want to look a the fuel filter and
pump because if the filters clogged with water "the ethonal has water in the
mixture" you will have to replace it. And the pump might be rusted all to hell
so you might want to replace that.