Eclipse GST 1997/ car running fine then terrible/ 4 codes

I was driving my 97 Mitsubishi Eclipse GST turbo yesterday and it was running fine I turned it off and ran into the store for 5 minutes when i came out and started my car it started running terrible. The idle dropped down to about 400 rpm and the car was running extremely rich. When I hit the gas the car would spudder like it wasnt running on all the cylinders I had no power and while trying to drive it , it would make a even pounding sound out of the exhaust the sound was not erratic but on time like a even spudder. I hooked up my Actron scanner and pulled these 5 codes P0115 (eng coolant temp circuit malf) P0110 (IAT sensor circuit malf) P0100 (MAF or VAF circuit malf) P0105 (MAP /BARO circuit malf) P1105 ( Manufac control Fuel air Metering) .. Other things I noticed ...before this all happened I noticed sometimes when I go to start the car it would not turn over right away it would just make a clicking sound, I would have to turn the key off and on a few times and then it would turn over and start. Also now when i start the car I notice my colling fan is on even though the temperature is below Cold. I also went down to autozone and bought a reman Air flow Meter and put it on. It made no difference at all.. Does the problem sound like a bad ECU? Any advice would help thanks

Rob