[SLESTAK75]

Welcome to the site. Since its quite likely that the carb had some ethanol gas left in it, there is a good possibility of it needing a good cleaning. When you say it happens when you drive straight, does this mean that its at wide open throttle? An easy check you can do is run it hard, cut it off and remove and inspect the spark plug to see what color it is. black is too much fuel, white is too much air, tan is just right. This will give you a better idea what to look for. Let us know your results.