Hyundai Forums banner

1 - 9 of 9 Posts

·
SENIOR MODERATOR
Joined
·
9,284 Posts
Discussion Starter #1
This morning I got in the car to head to work and she was idling really rough. If I got the revs above about 1500 it would smooth out but once down around 1000 or so it got REALLY rough. I shut the engine off and restarted it and though the roughness was still present, the CEL illuminated so I grabbed my scanner. A quick scan later I was presented with P0302 code for a cylinder 2 misfire. I checked the wires and everything was tight so as not to be late for work, I borrowed my mom's MDX and said I'd handle it tonight.

Cut to nine hours later, I arrive home and quickly pop the coil pack from cylinder two into cylinder one and vice versa. Upon removing the #2 coil pack I immediately noticed what looked like rust but on closer inspection, it appears to be scorching. The #1 coil looks just fine. After I swapped them I cleared the code and started the engine, expecting to get an immediate #1 cylinder misfire and rough idle but neither showed up. In fact the car runs just fine now though I'm not sure how long this will last. I do plan on replacing the coils anyway as they are original but I was looking for opinions.

Here's the photo of the #2 (left) and #1 coil packs (right).

Scorched Coil Pack by Andrew, on Flickr
 

·
Registered
Joined
·
168 Posts
I had a similar problem on a 3.0 L V6 Mercury Sable.
The problem would show up on high humidity days, like rain or snow and with a warm engine.
Otherwise, problem would not present itself.

Heat buildup in the COP forms the cracks over time, which open up and allow the high voltage to leak out to ground on high humid days causing my misfire problem.

I replaced the bad COP with a new one and the problem never reappeared again.

I would remove the suspect COP and check it for fine cracks with a magnifying glass.
 

·
Registered
Joined
·
417 Posts
IMO, that COP IS bad. I would just replace the "rusty" COP. At $25-$30, it is cheap insurance. It WILL fail catastrophically in the future, perhaps with no warning and at the most inopportune time. I wouldn't change out the other COP's. Let sleeping dogs lie.
 

·
Registered
Joined
·
941 Posts
I'ts more costly but I'd just replace all the coils and the plugs now. That way you know everything is brand new and same age.

Are they the original plugs/coils?
 

·
SENIOR MODERATOR
Joined
·
9,284 Posts
Discussion Starter #5
I'ts more costly but I'd just replace all the coils and the plugs now. That way you know everything is brand new and same age.

Are they the original plugs/coils?
I did the plugs about 9,000 miles ago and must admit I had a 'cheap [email protected]$tard' moment and skimped on the coils even though I knew they needed to be done. Coils are original at 106,000 miles.

I'm going to pick up a new set of four tomorrow.
 

·
Registered
Joined
·
785 Posts
My last car had misfire codes pop up at around that mileage on start-up, but it was due to clogged injectors. If the new coil/plugs don't resolve your problem then I think the injectors is the next likely culprit. Good luck.
 

·
SENIOR MODERATOR
Joined
·
9,284 Posts
Discussion Starter #7
Well I'm glad I decided to swap all four coils because it turns out #1 was the only truly healthy one left. #2 was the worst but 3 and 4 were close to being just as crisp. I'm hoping this also solves my warm start problem...it surely can't hurt it! :laughing:
 
  • Like
Reactions: NDSE

·
SENIOR MODERATOR
Joined
·
9,284 Posts
Discussion Starter #9
lovemysantafe,

Can we see pictures of all the coils ?

Were there a lot of cracks on the COP ?
Not necessarily cracks but they were generally starting to look funky. I can't get over how much better the car drives. It's got pep I'd forgotten it had and I actually spun the tires halfway through an intersection on an (experimental) full-throttle start. I didn't even know she could do that....

Fallen Soldiers by Andrew, on Flickr
 
1 - 9 of 9 Posts
Top