F250 runs but stops
 

My 1987 F250 5.8l V8 will run for about ten miniutes before it stops. then after about 30min it will do the same thing. what causes this or could correct the problem???

What we need to know is; does it restart easily?
If not, can you check for spark while trying to restart?
When was the last time you changed the fuel filter?

i recently replaced fuel filter and it restarts fine after a few minuites

We need to do some pinning down before replacing anything.
At this point we don't know if you are losing spark or fuel at the time of shut down.
If you have a testlite, you can run a wire from the coil primary terminal that doesn't come from the ignition supply to a point in the vehicle that you can connect the testlight to .Of course the other wire from the test light is clamped to a good ground.
When the engine is running that light should flicker as long as a signal is delivered to the coil. If it stops working at the same time as the engine begins to stall , it could be a spark related problem.
You could also get a can of carb and choke cleaner and when the engine quits , quickly spray some cleaner into the intake then try to start the engine. if it starts and runs even for a few seconds you may have a fuel problem.
It sounds like a lot of work , but it should help pin down the faulty system.
Once that is determined , we can go from there.

there was a recall because of distributor ignition modules cutting out as motors reached operating temperatures..check Ford service bulletins and/or talk with FoMoCo a service manager.I had a hell of a time getting the distributor out of my '91, 5.8 L...but got 'er done with my extensive vocabulary of curse words.