1992 Gmc Jimmy 4.3 V6 Cpi Vin W...code 42

[ENGINEMAN1]

HELLO TO ALL. I'M HAVING A MAJOR ISSUE WITH MY TRUCK WHERE IMMEDIATLY AFTER ABOUT 2 SECONDS FROM STARTING IT, IT SHOOTS ME THE GLORIOUS CODE 42. IT NEVER FAILS. I CAN EVEN CLEAR THE CODE AND EVERTHING BUT STILL NO MATTER WHAT STILL HAPPENS TO COME ON EVERY SINGLE TIME AFTER ABOUT TWO SECONDS AFTER TURNING IT ON. TRIED A NEW IGNITION CONTROL MODULE AND NO LUCK, TRIED NEW ECM AND NO LUCK. IT HAS A NEW DISTRIBUTOR AND ECM. CAR IS VERY DRIVEABLE BUT THAT IS ONLY BECAUSE ITS RUNNING ON BASE TIMING FROM ECM. I HAD PREVIOUSLY HAD A MAJOR ISSUE WITH THE ECM WHICH ENDED UP BEING REPLACED, SO AS I'M PUTTING THE ECM BACK IN ITS LOCATION, I DECIDED TO GO AHEAD AND REPLACE THE INSTRUMENT CLUSTER BULBS WHICH EVERY ONE WAS PRETTY MUCH BURNED OUT.SO I REPLACE THE BULBS AND SECURE THE ECM IN ITS LOCATION.. NEXT THING I FIRE IT UP AND HERE COMES A ROUGH IDLE AS WELL AS THE CODE 42 SES LIGHT. I TURN IT OFF AND TURN IT BACK ON HOPING IT WILL FIX ITS SELF AND NOTHING. IT DOES NOT IDEL ROUGH ANYMORE BUT SOMETIMES WILL SURGE (HIGH RPM TO LOW RPM) I DONT KNOW WHERE TO GO FROM HERE. ALSO ME AND MY BUDDY NEVER DISCONECTED THE BYPASS WIRE WHEN SETTING TIMING , COULD THAT BE A MAJOR ISSUE TO CAUSE THIS. BUT LIKE I SAID IT RUNS JUST FINE ONLY THING THAT AT IDLE, COLD START UP IT RUNS AS IF IT WERE ALREADY WITHIN OPERATING TEMP. (LOW RPMS). ANY SUGGESTIONS OR HELP WOULD BE GREATLY APPRECIATED. REMEMBER THIS CODE IS NOT INTERMITTENT. IT WILL COME ON EXACLTLY 2 SECONDS AFTER TRUCK HAS BEEN STARTED. PLEASE HELP...!!!!!!!!!