What could be wrong with my car?

Asked by Nov 05, 2015 at 02:02 PM about the 2004 Hyundai Elantra

Question type: Maintenance & Repair

I have a check engine light on, it keep saying it's the catalytic converter. We replaced that twice, it did say it was the 02 sensor replaced that twice. My car when it warms up or has been driven awhile feels like it is going to stall when stopped at a light. The rpm will also go from 1-3 and then below 1. We also replaced the brain, they thought it was that, there are no vacuum leaks had that checked out. I do not know what else to do.

3 Answers


The only thing left is the Muffler is clogged ... Take it to Midas before you spend a fortune on it .....2 Catalytic Converters ??????


Check the emissions decal under the hood. If you have California Emissions a Federal Emissions catalytic converter will not work. Check the wiring going to the downstream oxygen sensor. Make sure it's ok. HTH. -Jim


car has 2 02 oxygen sensor upper and lower and check flex pipe

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