I’ve seen a few helpful threads about the 2017 Elantra’s cylinder misfire and ignition coil issues. I had a misfire error at 44k miles and got a coil replacement under warranty. They replaced it with the updated design mentioned in the TBS bulletin. Now, at 97k miles, I’m facing another cylinder misfire—this time, it’s cylinder 1 (P0301).
I’m thinking about replacing the coil myself, but I’m not sure if I can find the new recommended design. Should I take the chance and pay the dealership’s $180 diagnostic fee, hoping they’ll fix it for free or at a lower cost?
Also, I’ve attached a photo. Does this mean anything to anyone? There’s no oil in the tubes, but there’s a lot of gunk buildup at the top. Is this just a sign of too many misfires? I just replaced the spark plugs.
I think that’s just grease, not corrosion. The ones I’ve checked out usually look like that, and it doesn’t always mean there’s a misfire or a bad coil.
If you’ve got the tools and know-how, I’d say pull the plug and coil from cylinder 1, swap the coil with cylinder 2, and the plug with cylinder 3. Clear the code and see if you get a miss on any cylinder (if you do). That way, you’ll figure out if it’s the plug, the coil, or something else like an injector or valve.
I had some misfires on my 2014, and after swapping out the coils, spark plugs, and injectors (one was kinda clogged), it turned out to be the crankshaft and camshaft position sensors.
So far, this is the only issue we’ve had fixed in our 2017 Elantra. We bought it as a certified pre-owned in 2020, and this problem popped up about a month after the five-year mark, so it wasn’t covered. Now, the lights turn on randomly when the switch is on auto overnight, and that just started a month ago. I hope it won’t be an expensive fix
Honestly, I feel you on the dealership frustration thing… I had a similar issue with my Elantra, and after getting ripped off for diagnostics, I just started tackling things myself. Replacing the coil isn’t that hard if you have the right tools. Just make sure you check if there are any recalls or updated parts available online before diving in. As for the gunk, it’s pretty normal with misfires, but keep an eye on it. Good luck
I had a misfire on my 2018 Elantra and went through the same dilemma. I ended up paying the dealership for diagnostics, and they charged me way more than I expected. If you feel comfortable replacing the coil yourself, go for it! Just look for the updated part number online or at a local auto parts store. That gunk might be a sign of carbon buildup, but it’s usually not a big deal unless it’s affecting performance. You got this
I totally get wanting to save money! If you’re handy, definitely try to replace the coil yourself. Just make sure you have the correct part first; some forums might have threads with links to where you can get the new design at a decent price. About the gun…yeah!!!, that’s a common issue with misfires, but as long as you replaced the spark plugs and there’s no oil, you should be okay. Good luck, and keep us posted on what you decide
