I have recieved the following codes from 1998 GMC

DTC P1345 CAMSHAFT TO CRANKSHAFT POSITION CORRELATION MALFUNCTION CONDITIONS.CHECK CMP SENSOR MAKE SURE ITS NOT LOOSE CAUSING VARIATION IN THE SENSOR SIGNAL EXCESSIVE FREE PLAY IN THE TIMING CHAIN AND GEAR ASSEMBLY.INCORRECTLY INSTALLED DISTRIBUTOR 1 TOOTH OFF IN EITHER ADVANCE OR ****** POSITIONS. CODE PO300 MULTIPLE ENGINE MISFIRE DETECTED CONDITIONS.THIS CODE WILL SHOW UP WHEN CODE DTC P1345 SHOW UP.YOUR PROBLEMS IS IN THE CMP AND CKP SENSOR.THEY WILL CAUSE MISFIRE IF TIMING CHAIN WORN WITH A LOT OF SLACK IN IT.CAUSING TIMING CHAIN TO SLIP ONE GEAR THROWING OFF TIME.THIS PROBLEM IS A DEALERSHIP FIX.THEY CAN CHECK TO SEE IF TIMING CHAIN HAS SLIPPED.THEY ALSO CAN CHECK VARIATIONS FROM CMP SENSOR AND CKP SENSOR.