QuestionI HAVE AN 01 ELANTRA GLS 4CYL 5SPD 2.0L, MY ENGINE WAS MISIFIRING AND THE CHECK ENGINE LIGHT CAME ON. REPLACED THE PLUGS, (NOT THE PROBLEM) ENDED UP HAVING THE COILS REPLACED. THEY CLEARED THE CODE BUT THE MIL CAME BACK ON. THE MECHANIC TOLD ME THAT IT HAD TO DO WITH MY O2 SENSOR OR CATALYTIC CONVERTER, AND THAT IT WOULDN'T BE A BIG DEAL IF I DIDN'T GET IT FIXED RIGHT AWAY, THE WORST THING THAT'D HAPPEN WOULD BE POOR GAS MILEAGE. THAT WAS ABOUT 2 MONTHS AGO. THE PAST FEW DAYS I'VE NOTICED THAT IT'S GUTLESS, IT'S THE WORST TODAY, I CAN STEP ON THE ACCELERATOR BUT IT TAKES FOREVER TO GO. THE ENGINE DOESN'T COUGH, CHOKE OR SPUTTER, IT ACTUALLY PURRS LIKE A KITTEN, IT JUST WON'T GO! ONCE I GET IT INTO 5TH GEAR IT KIND OF DECELERATES, BUT JUST BARELY, NOT LIKE IT DID WHEN I HAD THE MISFIRE ISSUE. I BOUGHT SOME STP FUEL CLEANER AND REVVED THE ENGINE TO ABOUT 5000 RPMS FOR 20 SEC OR SO, BUT IT BARELY HELPED. (MY UNCLE TOLD ME TO TRY THAT) IT'S VERY SPORADIC BUT ONGOING, SOMETIMES IT TAKES RIGHT OFF AND THE NEXT MINUTE IT'S SLOW AS MOLASSES! I'M A FEMALE WHO IS VERY PARANOID OF MECHANICS AND DEALERSHIPS, HAVING BEEN LIED TO ABOUT REPAIRS AND OVERCHARGED FOR WORK THAT WASN'T NEEDED AND/OR NEVER DONE. I HAVE A REPAIR MANUAL (SOMEWHERE) AND WONDER IF THIS IS SOMETHING I CAN FIX ON MY OWN? I'D LIKE TO SAY I'M MECHANICALLY INCLINED, HAVING REPLACED SPARK PLUGS AND WIRES, FUEL & AIR FILTERS, HEADLIGHT BULBS & HEADLAMP ASSEMBLIES, ETC. PLUS I CAN GET PARTS AT OR A LITTLE ABOVE WHOLESALE BECAUSE OF THE COMPANY I WORK FOR. I WAS TOLD TO TAKE IT TO AN EXHAUST PLACE SO THEY CAN TELL ME EXACTLY WHAT NEEDS TO BE REPLACED. DOES THAT INVOLVE A DIAGNOSTIC MACHINE? ANY INFO YOU CAN PROVIDE WOULD BE GREATLY APPRECIATED! I DON'T HAVE ALOT OF MONEY, AND JUST SPENT $800 GETTING THE COILS AND BELTS REPLACED.
AnswerP0422 indicates your catalyst efficiency is low. Most likely, a large amount of unburned fuel entered the catalytic converter when the car was misfiring and damaged the converter. Most likely, the converter is now largely restricted, causing a significant decrease in engine power. Imagine trying to breathe in while preventing yourself from breathing out. That's the same thing that's happening to your engine. Its inability to push exhaust out is limiting what it can take in.
The catalytic converter in question is part of your exhaust manifold. The manifold is covered for 10 years/100,000 miles for the original owner, and the catalytic converter is covered for 8 years/80,000 miles by federal mandate. If you fall within either set of conditions, take the to the dealer for service. Do not mention to them the problem with the misfiring. (They'll probably see the new coil and figure it out, though). Simply take it in and tell them that the check engine lamp is on and that you have a lack of power. If you're within either warranty period, that'll probably get you a new converter/manifold assembly without having to pay for it.
There's also a recall on 2001 Elantras to check for cracks in the exhaust manifold and replace the manifold if cracked. If this recall has not yet been performed and your manifold is cracked, you can have your problem fixed through the recall. Copy the vehicle identification number (VIN) from the vehicle and call a dealer and ask them to check whether there are any open recalls. If campaign V04 has not yet been performed, Hyundai is obligated to give you a new manifold/converter assembly if yours is cracked. But before embarking on this, you'll need to have someone put the car on a lift and look from underneath to see if the manifold is cracked. If you have the recall performed while the manifold is not cracked, the recall will be closed and you'll only be able to take advantage of the normal warranty avenues for manifold replacement.
