Cranks but does not start?

We should try to use starting fluid to see if the problem is spark or fuel, please go over this video to help you see which one it is:

https://youtu.be/lXLJbuAZ4CE?si=MeY3r1S_CTIKW6FH

This guide can help as well:

https://www.2carpros.com/articles/car-cranks-but-wont-start

Let me know what you find so we can continue to fix the car.

Okay, same car 2002 grand prix 3.8,I was getting code p0141 o2 sensor heater circuit malfunction bank 1 sensor 2,I bought a new o2 sensor, installed it now I'm getting code p0140 o2 sensor circuit no activity detected bank 1 sensor 2 can that cause my car to not start it seems to be happening every other day.

This code will not keep the engine from starting, when it cranks and worn start try starting fluid to see if anything changes. I have seen the fuel pump go out in these cars which sounds like what is happening.

But would it start one minute and 2-3 hrs later it'll turn over but won't start !

Yes, this is an intermittent problem which a fuel pump is known for.

Okay, I just got back, I tried starting fluid it almost started but ran down the battery, I just ordered a fuel pump cause I'm pretty sure that's what it is!

Okay, but can you please upload a short video of the engine cranking over, that way I can tell if the engine is hurt or not. I was hoping it would run with the starter fluid. If not, this guide can help you do a compression test. I don't want to install a fuel pump if that is not the problem :)

What guide ?

Sorry,

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.

Just letting you know the fuel pump was the problem, replaced it and it started right up,Thank you for your help !

Glad you could get it fixed, thanks for letting us know. Please use 2CarPros anytime we are here to help.