Please help with this problem on 2002 Mitsubishi Galant

I have an 2002 Mitsubishi Galant and it starts up but it will not stay started.It looses power. I got the brand new alternator i needed and the brand new battery and it's still not staying on.I took them out and got them tested again and that's not the problem. THe car just cuts off.(No noises,no shaking) What's the problem?

Asked by for the 2002 Mitsubishi Galant
There's no easy answer to this question, it requires a hands on diagnosis to determine why the engine is stalling.
2 more answers
I would unplug the mass air flow sensor located on the air snorkle next to the air box and see if it stays running. the mass air flow sensor may not be metering the air to the engine computer so your engine computer may be giving your engine too much fuel or too little. By unpluging the mass air flow sensor this will trick the engine computer to run on a predetermened fuel trim set by the manufacture. If your engine stays idleing and has more power I would test this part.