Did those have carbs? Or throttle body FI?
If it has a carb, you might check to see if there's crap in the float bowl,
my 73 ranchero had that problem.
Also, you might have an intermittent electrical problem, loose/corroded 12
volts to the coil, etc.

"aubrey" > wrote in message
lkaboutautos.com...
> my girlfriends car is a 1983 mustang auto in really nice shape except for
> a
> few problems like just quits running even on the highway what should i
> look
> at ???
>