1999 NISSAN MAXIMA Unknown Or Other Problems

I AM HAVING PROBLEMS WITH MY 1999 NISSAN MAXIMA. MY SERVICE ENGINE SOON LIGHT CAME ON ABOUT A YEAR AGO AND REGARDLESS OF WHAT I DO TO FIX IT, IT JUST COMES BACK ON. I HAVE HAD DIAGNOSTIC TESTS RAN ON IT AND IT HAS COME UP AS SOMETHING DIFFERENT EVERYTIME I FIX THE PROBLEM IT GIVES ME. SO FAR I HAVE FIXED TWO IGNITION COIL PACKS, A NOC SENSOR AND A COUPLE OTHER THINGS RELATED TO EMISSIONS. I HAVE SPENT AROUND $800 TO FIX THESE THINGS AND I AM NOW AM GETTING A CODE THAT SAYS THERE IS AN IGNITION MISFIRE. THE SHOP THAT I AM TAKING IT TO HAS TOLD ME THAT IT'S A PROBLEM THAT THEY CAN NOT FIGURE OUT AND THEY HAVE RESEARCHED IT AND BEEN TOLD THAT NISSAN CAN'T FIGURE IT OUT EITHER. *TR

AT COLD STARTUP, ENGINE OIL LIGHT USUALLY FLASHES, AND ENGINE MAKES LOUD SOUND LIKE IT DOESN'T HAVE OIL PRESSURE. THIS GOES AWAY AFTER A FEW SECONDS. NISSAN ADVISED TO ALWAYS USE NISSAN OIL FILTERS, WHICH I DO, AND PROBLEM HAS EXISTED SINCE CAR WAS NEW. WHEN CAR IS FULLY WARM AND IN DRIVE AT A STANDSTILL WITH LIGHTS ON AND A/C OFF, CAR IDLE WILL DROP TO ABOUT 500 RPM, CAUSING ANNOYING VIBRATION. DEALER SAYS NO PROBLEMS FOUND. RESUME ON CRUISE CONTROL HAS FAILED INTERMITTENTLY ABOUT 1 OF EVERY 20 TIMES. RESUME FEATURE WILL NOT WORK, AND YOU MUST RESET THE CRUISE TO THE PREFERRED SPEED. DEALER SAYS NO PROBLEMS FOUND. DOOR LOCKS/KEYLESS ENTRY HAVE FAILED SEVERAL TIMES. POWER LOCKS HAVE LOCKED AND INSTANTLY UNLOCKED WHEN PRESSING LOCK BUTTON ON KEYLESS REMOTE; ALSO, LOCKS HAVE UNLOCKED AND THEN LOCKED WHEN PRESSING UNLOCK BUTTON AND HAD TO MANUALLY UNLOCK EACH DOOR....

FOUL ODOR THROUGHOUT CAR WHEN STANDING OR MOVING(ROTTEN EGG SMELL)

FOUL ODOR THROUGHOUT CAR WHEN STANDING OR MOVING(ROTTEN EGG SMELL)

FOUL ODOR THROUGHOUT CAR WHEN STANDING OR MOVING(ROTTEN EGG SMELL)

FOUL ODOR THROUGHOUT CAR WHEN STANDING OR MOVING(ROTTEN EGG SMELL)

FOUL ODOR THROUGHOUT CAR WHEN STANDING OR MOVING(ROTTEN EGG SMELL)

FOUL ODOR THROUGHOUT CAR WHEN STANDING OR MOVING(ROTTEN EGG SMELL)