car cranks over but wont start help please battery is good ?

three things make your engine run. Air, gas, and spark. Start with the basics first check that you are getting each one. We know you probably have air unless your exhaust is plugged up in some way or your air filter is dirty. On foreign models, some won't start unless you have the entire air induction system in place. Also. a plugged catalytic converter could cause it not to start. If you think that is all ok, then check to see if you have spark at the plugs. If not then the starting circuit has a problem. If that is ok, then you still have a problem with the gas getting to your engine. Move the accelerator and see if there is any gas being sprayed into the intake.If you think that the intake components are ok, then check to see if you are getting any gas to the engine. Could be your gas pump has gone out.