I have a 1999 Mitsubishi galant DE, 4Cyl, Automatic. This morning when I started the engine, it started fine but it only run for no more than five seconds and then it shut down, I try starting the car again a second time and it did the same same thing but this time the check engine stay on. Basically the car starts up but it only stays running for no more than five seconds and then it shuts down, Check engine light stays on. Any ideas of what might be causing this problem???
That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.
Do post the code(s) when you get it(them).
But you may be having a problem with your idle air control valve (IAC). Try this: start the car and hold the accelerator pedal down slightly as the car starts. If it keeps running it is almost surely the IAC. Do not buy a new IAC (yet). The electrical connections to the IAC ought to be cleaned and checked for voltage. The IAC itself can be cleaned with some throttle body cleaner or similar. Or the IAC could be dead but you want to be sure since they aren’t cheap.
Of course, the IAC remains a guess.