BUICK: LOOSE COIL GROUND WIRE. SERVICE PROCEDURE TO CHECK THE COIL GROUND WIRE AT TWO LOCATIONS ON CERTAIN VEHICLES EQUIPPED WITH A V6 ENGINE (RPO LF1/LLT). THESE VEHICLES MAY HAVE A LOOSE COIL GROUND WIRE, WHICH COULD CAUSE THE ENGINE TO RUN ROUGH, MISFIRE, OR CAUSE THE SERVICE ENGINE SOON LIGHT TO ILLUMINATE OR FLASH. BULLETIN IS REVISED TO EXTEND EXPIRATION DATE TO 9/30/11. *PE