I just did a road trip from Chicago area to Mill Run Penn to see Fallingwater and took 1992 NSX. Car ran great but after 3 or so hours speedometer quite and TSC & Check engine lights came on. Turning off the car and restarting got everything back to normal for very short period then happened again. Second day same thing. Then problem seemed to go away only to come back on longer drive back home. This time speedo quite first then lights. Thinking heat related problem, very warm first days, but coming back cool. Any ideas???