cold & idle problem

This is my first thread the this forum.

Experts, i have a 1996 gdi rhd galant (manual transmission). whenever the engine is cold, it does not remain on at first start, it just dies innediately as if i turned the key back to the off position. On the second attempt it will start, goes to 2000rpm to bring temp up to operating value, after which it idles at 750rpm (which is ok). If i turn the a/c on while the engine idles, the a/c kills the engine; rpm has to be maintained above 1500 to maintain the a/c. if i suddenly depress the gas pedal at idle speed it kills the engine. So, to move off from standstill i have to very, very slowly depress the gas pedal to allow rev to go up above 1000rpm. whenever i come to a standstill and neutral the car, the rpm needle fluctuates all over the place before settling at idle speed (750rpm). I used the throttle body screw to up the idle speed to 1000rpm, but , two or three day later the it went right back to 750rpm.

I have done the necessary basic tune up: new gas filter, plugs, engine oil/filter change, etc. I've also cleaned the throttle body.

I heard that the gdi galants have a second fuel pump that runs off the cam-shaft. these pumps,they say, have filters, which, if are dirty will cause the car to behave the way i described. Could this be where the problem lies?

Not very many of the members here own "JDM" galants....especially with the GDI motors. Mitsubishi of america doesn't have a vehicle in the U.S. lineup with a GDI motors...MIVEC was just recently introduced in the current "regular" version Lancer. Sounds like you did the troubleshooting steps but it may be bad temp sensors.