My tercel sometimes gets stuck on 2nd gear while driving on the freeway. It doesnt happen all the time but it usually happens once a trip. For some reason it stays on 2nd unless I slow down to under 50 mph and stomp on the gas till it goes back to 1st gear and upshifts to 2nd and 3rd. Is there an adjustment that needs to be made? What could the problem be? by the way the tranny never slips. Thanks