What could be wrong with my 07 Mitsubishi eclipse it was
submerged in a lake for 15 minutes after I got the water out
of the motor and such I tried to turn the key a few days later
and the key light flashes it tried to turn over wouldn't start I
think maybe a computer
The whole car or partially Submerged? All the electrical components are suspect now and will need to be disconnected and dried out and gone over. All the fluids like oil and transmission fluid and fuel should be changed too. Did you contact your insurance company?
I did change all the fluids dried it all out I only had liability so I lost out it was stolen and completely submerged in the lake only the trunk was showing
Did you remove the spark plugs and remove the water from the engine cylinders?