Oldsmobile/Buick Repair: 89cherokee, auto shut down, computer hope

Question
I HAVE A 89 CHEROKEE 4.0 ENGINE. I'AM THE SECOND OWNER I BOUGHT IT FROM MY FRIEND AT 143,00O MILES RUNNING LIKE A CHAMP, IT NOW HAS 2OO,603 MILES AND STILL RAN GREAT THAN ONE MORNING I WENT TO START IT IT TOOK AS LITTLE LONGER THAN NORMAL TO START&LACKED POWER WHEN IT DID START? WELL IT RAN FOR ABOUT 7 MINUETS AND SHUT OFF AS THOUGH THE KEY HAD BEEN SHUT OFF WOULD NOT START AGAIN FOR ABOUT FIVE HOUR'S. AND WHEN IT DID AGAIN 7 - 10 MINUTES AND SHUT OFF AGAIN FOUR OR FIVE HOURS LATER START'S AGAIN AND SAME THING HAPPENS. I HAVE CHANGED THE COIL&IGNITION MODUEL TRIED 3 DIFFERENT UNITS A NEW DIST&COIL PICK UP.ALSO ONCE IT SHUT'S OFF I'AM NOT GETTING ANY SPARK LEAVING THE COIL IT SELF FOR ABOUT 4 5 HOURS ? BUT 1 OUT OF MAYBE TEN TRY'S I CAN START IT RIGHT BACK UP AND IT WILL RUN FOR ABOUT 7 MINUETS IHAVE GONE THUR EVERTHING THE BOOK SAY'S. NEED SOME EXPERT HELP. THANK YOU VERY MUCH FOR YOUR TIME .GOD BLESS

Answer
hi james,well this is going to be a tough one.i see you have been very theral in your troubleshooting.you are loseing power to the coil from the ignition.possible auto shut down relay.find this in your relay center.if not the relay possibly the wire under the relay.if not these only thing really logical would be the computer.hope this helps please rate my service.ty billymac