2012 HYUNDAI ELANTRA Engine And Engine Cooling Problems

I ACCELERATED OUT OF A PARKING LOT AND THEN LOST POWER BECAUSE THE CAR WENT OUT OF TIME AND STARTED MISFIRING. THEN WHITE SMOKE STARTED COMING OUT OF MY TAILPIPE. THE CAR BEHIND ME ALMOST HIT ME. THIS IS THE SECOND TIME MY CAR HAS MISFIRED. THE CHECK ENGINE LIGHT CAME ON. THE REASON I KNOW IT MISFIRED IS BECAUSE I HAVE A CODE READER AND IT SAID CYLINDER 1 & 2 MISFIRE. I PULLED OVER AND TURNED OFF THE CAR, WAITED ABOUT 5 MINUTES, RESTARTED IT AND THE CAR RUNS FINE. THE DEALER CANNOT DO ANYTHING ABOUT IT BECAUSE THEY CANNOT RECREATE THE PROBLEM AND BY THE TIME I GET THE CAR TO THEM THE ENGINE LIGHT GOES OFF. STRANGE BEHAVIOR WITH THIS CAR.

THIS INCIDENT HAPPENED THE NIGHT I BOUGHT THE VEHICLE. THE VEHICLE WILL SUDDENLY BUCK/JOLT/JERK AS IF HITTING A SPEED BUMP IN A VERY JARRING MANNER. THIS ALSO HAPPENED DURING A TEST DRIVE OF A VEHICLE OF THE SAME TYPE AND COLOR (I'M NOT SURE IF THEY SOLD ME THE ONE DURING THE TEST DRIVE.). I WAS INFORMED THAT THE VEHICLE WHICH JOLTED IN THIS MANNER WAS REPAIRED AND SOLD TO ANOTHER CUSTOMER. I'M NOT SURE IF THEY WERE TELLING THE TRUTH OR IF THEY GAVE ME THE SAME VEHICLE. STILL, THIS IS A SERIOUS DEFECT THAT IS POTENTIALLY A BIG SAFETY HAZARD. THE SALESMAN WHO SAT NEXT TO ME WAS ALSO CONCERNED WHEN THE INCIDENT OCCURRED TWICE IN THE SPAN OF ONE 10 MINUTE TEST DRIVE. I BOUGHT A BRAND NEW VEHICLE NOT EXPECTING THIS TYPE OF SERIOUS, INTERNAL ISSUE. AFTER SOME TESTING, I BELIEVE THAT THIS SUDDEN BUCK WILL...