I have a 2010 base mustang with the 4.0 L engine and It will NOT engage the starter on occasion. I turn the key with the clutch depressed and the starter will NOT engage. The problem seems to crop up when I have traveled a few miles locally and need to restart the car after it has sat locked and shut down for a short period of time. The other electrical elements in the car work, lights, radio & A/C fan when the key is engaged and in the "on" position. I have replaced the battery and plugged in one of those computer check applications and the reading is " no problems ",........I had it into a repair shop, they had it for two days and the car NEVER acted up for them,.... could it be the switch on the CLUYCH pedal?,. I am at wits end as this problem comes and goes on a whim by the car,.. I can't understand why it is so random????