NHTSA Complaint #10192554 — 2000 PONTIAC GRAND PRIX

STARTING WITH A MAF SENSOR GOING OUT, REPLACED, CAUSED DAMAGE TO O2 SENSORS, REPLACED ,AS SOON AS THESE WENT OUT NOTICED COOLANT LEVEL DROP THEN THE COOLANT LEVEL SENSOR WENT OUT AT TANK, REPLACED, NEXT MORNING AT START UP A LOUD KIND OF KNOCKING TOOK PLACE AT START UP FOR 5 TO 10 MIN AND VERY ROUGH IDLE FROM 1500-2000 RPM ,PO300 RANDOM MISFIRE, SO I REPLACED PLUGS , WIRES , AND COILS. NOW RUFF RPM RANGE 1000 TO 1500 AND STILL KNOCKING AT START UP. CHANGING OIL AND FILTER AFTER ALMOST EVERY FIX TO CHECK FOR WATER OR METAL, OIL IS FINE,NOW A PO304 -RANDOM MISFIRE ON 4TH CYLYNDER- BUT CAR WOULD CLEAR UP FOR A DAY OR TWO,ALSO ADDING INJECTOR CLEANER AND FUEL FILTER TO MAKE SURE FUEL SYSTEM IS OK AND USING A NOID CHECK ON EACH INJECTOR ALL INJECTORS FINE, NOW KNOCKING AT START UP WENT AWAY ,BUT ROUGH IDLE STILL PERCISTS . STILL PO304 SO I CHECK COMPRESSION ON THE 4TH CYLINDER AND IT ONLY HAS 70-75 LBS. OF PRESSURE. SO I'M DONE WASTING MONEY BRING IT TO THE GILROY PONTIAC BUICK GMC FOR TEAR DOWN AND FIRST THEY SAW A BURNT EXHAUST VALVE ON THE 4TH CYLINDER , THEN NOTICED THE WATER IN THE VALLEY TRAY AND HEAD GASKET IS BLOWN AND THE INTAKE GASKET IS LEAKING AND THE WATER PUMP IS LEAKING THE SAME WATER PUMP THAT WENT OUT AT 700 MILES NEW. SO NOW THE ONLY CHOICE I HAVE IS TO HAVE THE HEAD AND VALVE JOB DONE, BUT THE WATER DAMAGE WOULD MOST LIKELY CAUSE PINGING AFTER ALL THAT MONEYS SPENT SO NOW ONLY CHOICE IS TO PAY ALMOST $4500 FOR A NEW MOTOR , PROBLEM SOLVED.AT 92000 MI