i have an 86 and after 30 or so miles the engine will just cut. i turn the key off and then on and it runs just fine for another thirty miles. Any thoughts?

 

Reads like spark issue, and heat in the spark system.

Does it start back up immediately?
Or will it take a few minutes before it restarts?


TFI module on the distributor and the coil can get heat sensitive.


I wouldn't think fuel issue, but.............try loosening the gas cap and driving.
EVAP system is designed to pull fuel vapor out of the fuel tank while driving, if tank isn't venting then negative pressure can build up in the tank, this prevents the low pressure pump in the tank from pushing out enough fuel and engine stalls.
Turning key off vents the tank and you start over

The in tank fuel pump has a screen around it, in older vehicles this screen can get clogged up, once fuel demand exceeds flow thru the screen the engine dies, I would expect the drive time after the restart to be shorter than the original stall time through.
And I would also expect that with a heat issue, after first stall run time should be shorter

 

i will try the gas cap thing. it starts right back up after stalling.

 

Any codes set? Do you have a code reader? If not, most auto parts stores will connect a pertable OBDII reader to your port (under the dash) and see if you have any codes stored. This could help in pointing to a fault location.

If it starts right back up, it would not sound fuel related, although loosining the gas cap to see if you have a vapor lock (you'll hear a "whooosh" sound when opening the cap) won't hurt. Just don't leave it open, or this will set a code.

Sounds ignition related to me. Heat build up can make the ignition igniter "open". A weird situation happened to me once where the O2 sensor was literally dead on a Pointiac I knew of, and that was causing this vehicle to stall at highway speeds. Never did figure out why that was; it did not through a code either.