After driving InfinitiG20 for about 15 minutes, the MPH guage, RPM guage and temp guage goes to zero. The electronic guage that tells you how many miles you've driven will not register. There doesn't seem to be any problem with the engine, the car runs fine when this occurs. If you stop the engine for a while and restart the car the guages work fine for awhile and the same thing occurs. the mechanic couldn't find a problem. Help!