FIRST OFF YOUR TRUCK IS AS YOU SUSPECTED A 95.5 SO IT WILL NOT HAVE A DATA LINK CONNECTOR LIKE THE 96 PRODUCTION FOR 96 VEH STARTED 11-95 , THE SYSTEMS YOU DESCRIBE SOUNDS LIKE YOU HAVE A BAD 02 SENSOR , CEL INTERMITTENTLY AND BLACK SMOKE , AND BOGS DOWN. THE CONNECTOR YOU ARE LOOKING FOR IS THE WHITE 3 PIN , WITH A SHORT JUMPER WIRE CONNECT THE TWO OUTSIDE TERMINALS 1AND 3 TOGETHER WITH THE KEY AND ENG OFF, NOW TURN THE KEY TO THE RUN POSITION AND THE CEL SHOULD FLASH THE CODE THAT IT HAS STORED, IT SHOULD FLASH 12 THREE TIMES AND THEN THE FAULT CODE OR CODES WITH THE LOWEST NO, BEING FIRST AND THEN ON TO THE NEXT . NOW AFTER YOUR REPAIR YOU MUST CLEAR THE ECM OF IT,S STORED CODES ,TURN OFF THE KEY REMOVE THE JUMPER WIRE AND DISCONNECT THE BATT + TERMINAL, NOW WITH THIS CABLE DISCONNECTED YOU CAN WAIT ABOUT 5 MINUTES TO CLEAR THE ECM, OR YOU CAN TAKE A JUMPER WIRE AND DO IT THIS WAY TO GUARENTEE CLEARED CODES , BUT LISTEN CLOSE TAKE THE JUMPER WIRE OR USE THE +BATT CABLE THAT IS DISSCONNECTED FROM THE BATT IF IT WILL REACH AND HOLD IT OVER AND TOUCH THE GROUND CABLE AND HOLD IT ON THE GROUND POST , WHILE DOING SO HAVE SOMEONE TURN THE KEY BACK TO THE ON POSITION FOR JUST A SECOND OR TWO IS ALL IT TAKES , TURN THE KEY BACK OFF AND HOOK THE CABLE + BACK TO THE BATT ,THIS WILL CLEAR ANY AND ALL MEMORIES IN THE VEH, RADIO OR WHATEVER JERRY