My friend owns a 2003 Mitsubishi Mirage and it will not idle at all. It starts and will run about 5 seconds and turn off, but if you slightly press the gas it will run fine. We did a complete tune up, including fuel filter, checked for vac leaks, but still does it. A mechanic says it will cost $500 to fix it, but i am sure it is something simple that i can fix and save my friend some cash. There check engine light never comes on, so there are no codes stored in the computer.