Car won't start without a push

Are you saying it will not start, or will not crank ?

Could be a battery cable connection, faulty starter, or the neutral safety switch. You would need to know if you have battery power at the starter terminals when it fails to crank.

What happens when you try to start the engine with the key? Does the starter motor turn over the engine normally? If yes, the problem isn't the starter motor.
If the starter motor doesn't work at all, or works but struggles to turn over the engine, there are four likely possibilities: a bad starter, a bad starter relay, a bad ignition switch or a weak battery.
Even if a battery shows 12+ volts, that doesn't mean it has enough power to turn the starter (because it's not just the voltage that counts ... it's the number of amperes (quantity) of electricity that can be delivered.)
The fact that your car could be push-started suggests that the problem is somewhere in the battery/starting circuit -- not elsewhere in the engine. If the battery is good (most auto parts shops -- at least in the US -- will test it free), you need to figure out if the ignition switch is getting power to the starter relay, and if the relay is getting power to the starter. If "yes" to both, the starter is bad.

You need to have your flywheel: replaced.Your starter motor engages against the fly wheel at the back of the motor. Every time your motor stops it tends to be in the same few positions (just the way things work) so there is more stress on some parts of your fly wheel than others. Because of this the teeth wear out on the fly wheel which means the starter can correctly engage on the fly wheel which is the grinding noise.

It sounds like you have a bad actuator. This is attached to the starter and has a solonoid that pushes the starter motor gears into the engine gear. If the solonoid is faulty this may happen. Also check alignment of the same.

It sounds like you have an issue with your PassLock security system. I had the same with my 2002 Impala. Key turns OK, but won't start, won't crank. Wait 20-30 minutes, and car starts normally. There is usually a clue from the Battery and Security lights.
The problem starting to happen once a month, and eventually 1-2 times a week.
There are several write-ups on this problem for several GM cars for 2000-2006(?). Search this website, and search the web.
The official solution is to replace the ignition switch. The best solution is to bypass the Pass Lock system. I went ahead and did a full bypass, which involves cutting wires and adding resistors to the ignition circuit. I have not had a problem since.

If the engine is running when you try to use the starter, it won't flood the engine, it is already running. What happens is the starter gear tries to lock into the flywheel and this causes the starter to spin faster then it is supposed to. It is likely you damaged the starter and it needs replaced. You can remove it and have Auto Zone test it for free.

Hi this sounds more like a starter motor problem, what you can do is locate the starter motor on your vehicle, using either a long bar or a hammer tap the starter then try turning the motor..if that does not work, get someone to help tap the starter while you turn the ignition at the same time this should free the solinoid on the starter, once you have started your vehicle, turn it off and try again without tapping the starter motor, if it fails to turn over then you will need a new starter, if it starts as normal, turn it off 2 or 3 more times just to make sure it continues to start hope this helps please vote thanks good luck

did you use a new starter or a used one,if it was a used one it or the solenoid may have a problem if its a new one it still could be a bad new starter or solenoid(it happens).you may have a dirty ground where the starter bolts to the motor that the surface may need to be cleaned,or it may be dirty wire connections at the starter solenoid or connections not tight(?).i assume when you had the battery tested at the shop you didn`t have them perform a starter test.some times it can take several attempts to catch the starter acting up.

Check the connections at the battery, and starter. If any one of these cables are loose, it will cause this.
Thanks