sometimes my 98 mustang gt starts and runs great and sometimes it will only turn over and not start. I have replaced battery fuel pump,plugs, crank sensor. The theft light flashes rapidly when it won't start. This car has a different drivers door and an aftermarket horn (which I disconnected). I noticed that if the fan cuts on as soon as I turn the key it will not start and also if it's cooler outside it won't start Can anyone help me?