Ford Repair: security system will not allow eng 2 atart, security light, security issue

Question
I have a problem with 2000 Mustang. The motor will not start, but will crank. Have been told that the security system will not allow motor to fire? Did put some 10% ethol gasoline in the tank and did not use the car in about three weeks. But have done this before with no problem

Answer
First, observe the security light when you try to start, if it blinks rapidly then you have a security issue. Checking codes will verify this. If the security light proves out normal, then you will need to determine if you are missing spark or fuel. Does the CEL go out while cranking?