Trane air handler blower not always running

I'm having the same problem after 9 years of flawless service from my Handler, ive had a tech out here and they can't seem to find a problem, they checked the wiring behind my thermostat in my air handler, checked voltage, he doesn't seem to think that its the blower because he says that usually they either blow or don't or make some sort of noise if going out, the blower blows at full speed and when it does it doesn't seem to have any problems doing it and seems to think its the fan control board but really isn't sure and is calling Trane in the A.M.
What are the chances that its my actual Thermostat causing all of these problems?

Its starting to drive me nuts all of this turning on and off and sometimes not coming back on until I raise it above the temp in the house for 2 mins and then lower the temp back down a couple again until it decides to come on again.