I have a Jeep Grand Cherokee 1996 V6. Recently I turn on the jeep and was talking on and car turns off. I turned it on again drive and while at a red light my jeep turns off. I dropped the Jeep off at my mechanic, whom could not get it to turn off. I get Jeep back drive it around, park it, drive it and while waiting for a red light it turns off. Any ideas what could be wrong…?