car will turn over but won't start.

The best thing to do is to scan the data stream while you are cranking the engine. This way you can see what is and is NOT working. I do this all the time when I am diagnosing a no start. The other thing is to check for codes, there may be some n there that lead to an answer. As you have found out, just trying parts can be frustrating and expensive, though we have all done it. Good Luck!

i have a 2001 monte smae promblem other day went to auto zone they replaced air filter and were the full throttle body is ask they will show you there is a place were you can idle the engine by hand keep idling it theres a piece of trash stuck in it will blow it out car crank and ran fine after this

Fuel Injector Pressure Regulator.