Took a trip from Miami to Orlando. The first problem I found was a stall when I pulled in for gas after 2 hours of 75mph driving. The car restarted immediately. No more problems until return, when the car started losing power (bucking or misfiring) after three hours drivnig hyway. If I let up off the gas it got worse and seemed to even start the problem. Stopped and restarted after filling up on gas, kept the speed under 70, the car ran cooler and the bucking stopped. It did stall once more through a toll booth, as I let up off the gas to slow down. Any suggestions?