Would an ignition coil go bad twice on the same cylinder in a 2012 Hyundai Elantra?

Question

My 2012 Hyundai Elantra had a check engine light at about 19K miles, and I don't remember the code at that time but it had to do with coil 4 being bad.  The dealer changed coil 4 at that time.  The car now has 50K miles on it, and the check engine light came on again, and it had a P0304 code - cylinder 4 misfire.  What is the likelihood that coil 4 is bad?  I'm asking because the dealer just changed that coil 4 again saying that there was an internal short in that coil.  I would think that more testing should have been done, and the dealer disagrees.  They didn't believe that there could be something wrong with the fuel injector or something else.

Answer 1

HI there,

If the coil was tested and found to have an open internal ground then it's quite likely it was the problem. It is possible something would be causing the coil to fail, such as a poor engine ground or possibly a bad spark plug that has high resistance, however their diagnosis that the coil is bad shouldn't be suspect. They should stop there once the problem is located.