Originally Posted by RVGRINGO

You may drive any properly registered car in either Mexico or the USA with either a US or Mexican driver's license. In fact, we have both US and Mexican driver's licenses ourselves and also have a US plated vehicle as well as an Jalisco registered vehicle. It is actually easier to drive the Mexican car in the USA because there is no need to stop for an auto importation sticker and that is one less expense.
If stopped in the USA, show your Mexican license and your FM3. You might be less likely to get a ticket. In Mexico, we show the US license just in case they want to keep it. You can get a replacement for a 'lost license'. So, when in the USA, try to get another US license if you can.......