My Mustang 2000 will turn over but won't start. What's wrong with her?

Just because you hear the pump come on does not mean it is working. Remove hose from throttle body and spray some starting fluid or throttle cleaner into throttle body reinstall hose then try to start vehicle if it starts then shuts off fuel pump not working.

Just reread your question and if it is not cranking over at all have someone tap on starter with a hammer and try to start vehicle at the same time if it starts replace starter.

It sounds like it is out of gas is what it sounds like. I dont think I asked the question right.

Do what I suggested in first answer.

ok Ill let you know how it goes

Is the engine turning over with the new battery? Did you clean the battery terminals and the cable ends and make sure they are on tight?

firebird338 I tried what you said to try and it did the same thing. Just sounds like it wants to crank up but never actually does. Yes the terminals are good and are on tight. it tries to start up but doesnt

First you have to determine whether or not the pump is pumping either have a fuel pressure test done or you can remove the fuel line from the fuel rail and put the end of the fuel line in some kind of container like a large glass jar and have someone turn the key to the on position ( do not try to start) observe how the flow of gas goes into the jar should be a nice strong stream of gas if none at all or a weak stream comes out replace fuel pump.