I have a 2004 Chevy impala and when I go to turn it on it cranks but won't start until I push on the gas, but then sometimes it starts fine, also the car will just shut off while I'm driving, usually while in traffic at low speeds. I have changed the fuel filter and fuel pump but with no success. Any ideas?

Have u checked the catalytic convert in the exhaust or the muffler to be sure they are not plugged. If one of them are it will not allow fuel to be pulled into the engine. I had the same problem with my truck and when I put starting fluid in it would run.

when you say -turn over do you mean firing-turning over to me means the starter motor is cranking or turning over-firing is when combustion happens in the cylinders-as far as the cranking continuing-try some wd40 in the ignition switch-it may be hanging up-Denny

I would start by checking the basics which are checking for spark and fuel. If you have a gauge, check to see if you have fuel pressure when the key is turned on. If you have fuel pressure, check for spark. Chrysler products are known for the crank shaft sensor to go bad and cause a no start. Also, if driving for a certain period with the pedal depressed at the same speed, the throttle position sensor will stay at that position if stuck and will cause either and driveability problem or stalling. You may wanna look into replacing or at least checking that. Good luck.

i would say when the person broke into your car they set off the security system which stops the car from starting, the way to reset the security is to put your key into the ignition turn the key until all the dash lights come on and let them stay on about 15 minutes after the 15 minutes have expired turn the key off and wait about 3 seconds and then your car should start. hope this helps.

check for your cam sensor or crank sensor .

Check your cam and crank position sensors. Check the fuel pressure regulator and then the Fuel pump itself. This sounds stupid, but go check the gas cap too and make sure it is on tight. Sometimes it's the little things..haha. The two sensors tell where the crank and cam are in relation to each other and TDC of Piston 1. If one of the sensors is out of whack...the whole timing process will be thrown off. Most of the time if the cam sensor is bad, the car won't start, if the crank, it will start but run like ****. They don't cost much usually and your car is old enough that they should be replaced anyway. The MAF sensor would just cause the car to run rough most of the time if it were faulty or dirty. But being how generalized those codes are, it's never fun to figure out. Hope this helps you :)

You'll have to figure out if it is a fuel or ignition problem.
Is the check engine light on ? Have you checked for trouble codes ?
It could be a relay, the ignition module, coil, fuel pump, or a list of other things.
Could even be a problem with the security system.

The alternator is not charging,or the battery wont take a charge.If all accessories work fine when its running after you've boosted it,its likely the battery.
John

It sounds like your ignition module is starting to go bad. As it gets worse it will be harder and harder to start, until it doesn't start at all. Your crankshaft sensor could also be going bad. Hope this helps.

check the ignition switch