1999 Nissan Maxima UNKNOWN OR OTHER

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

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)