Hyundai Forums banner

Would a spark plug go bad suddenly?

7K views 7 replies 7 participants last post by  TurboRev 
#1 ·
My Sonata was running fine before. Then the next time I started it up it was rough idling, from then on. I know people recommend checking the spark plugs but would a spark plug just fail like that or would it be gradual? Thanks
 
#2 ·
our blue car(just 13k miles) developed a rough idle that got worse. we finally took it in, after a few months. it was a spark plug with a crack in the insulator. i didnt see it, but that is what they diagnosed. new plug installed, and it runs fine. if your car has a cop system, i would suspect a coil, too. i was surprised at the broke plug, because i would think it would throw a code, but the ce never lit up
 
#3 ·
Yes it can. It is a small component subject to huge forces, massive heat and very high voltages not to mention the vibrations of the engine. it has a porcelain insulator which is not the most robust of materials. I would think it would be highly likely that a spark plug could fail instantaneously and I am surprised that many more don't.
 
#4 ·
It's not common for them to fail but they do. With all the modern cars having Coil On Plug design the coil pack could also be the culprit. It sounds like the plug probably had a factory defect that with time and vibration was subject to premature failure.

Sent from my Nexus 6 using Tapatalk
 
#5 ·
My Sonata was running fine before.
Ok

Then the next time I started it up it was rough idling, from then on.
Ok.. Have we actually scan the thing to see what circuit the PCM may have flagged for fault (DTC)..

I know people recommend checking the spark plugs but would a spark plug just fail like that or would it be gradual? Thanks
That engine has DENSO IRIDIUM plugs in it,, unless somebody change them..

See random center porcelin crack up in the shell and fall down, thus shield spark from developing.. seen a pile of broken intake gasket at cylinder 1 on the 2.4L,, that why I ask if we scan the thing,, quick test be to have engine idle, and spritz some carb spray at intake runner 1 at cylinder head,, see if it go crazy (vacuum leak)...

Dont see coils on the 2.4L.. though that age, anything possible.. start with scan, see what comes up, go from there

Just replaced timing chain on a 2.4 NF here this past week, stretch, jump, codes, not run for crap, hash noises at front of engine, Moe, Larry & Curly Service Center replaced P/S pump,, engine still run like crap and have noise,, go figure..
 
#6 ·
Yes a spark plug can suddenly go bad, well kind of, they wear, but they don't misfire sometimes, and then sometimes not, it either works or it don't, there is no intermittent. It's easy enough and cheap enough to replace spark plugs so I would just do it, that knocks that problem out of the equation.

Sent from my SM-G930P using Tapatalk
 
#7 ·
Just an FYI update, turns out it wasn't the spark plugs, any sensors or bad wires/connections causing the rough idling. It was a failed A/C compressor which was apparently seizing/not spinning properly and screwing up the running of the engine, even when the A/C wasn't being used. Had the A/C compressor replaced and it's running normally now.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top