Update: so got home and tried to pull the plug.... but there was no plug. Took a pic on my cell to see what's down the hole. Nothing. I'm guessing I didnt tighten the plugs enough. I put the #1 cylinder spark plug in #4 and it went in fine. So im going to order 1 oem coil pack and a new set of plugs. I hope that's it!











So I was on the highway doing 70mph. All of a sudden I hear a noise coming from under the car towards the engine. I pulled over. Honestly I thought it was a exhaust leak. Thats how it sounded bc it was loud. No check light came on either. Idle was rough going 1000rpm to 2000rpm up and down. So I popped the hood and started the car. Putting my hand around the engine to feel for ait and found a spot. It was my coil pack #4 I believe. It was popped out of the head and hanging on to the wiring clip. The coil broke in half and the size 10 mm bolt that holds the coil down is still on the valve cover! I never beat on the car. Always babe it and never let me down. Its a 2008 with 209,xxx miles manual transmission. I'm mechanically inclined. Ive been working on cars from swapping engines, oil changes and turbo charging a few cars. But never seen or heard of a coil pack breaking like this. I changed the plugs to oem ngks at 198,xxx miles. I unplugged the broken coil pack and drove home (5 mins away from where the car started acting up). Check light started blinking when I drove it. I know that means not to drive it when a check light starts to blink. Anyways drove home ok with the rough idle. Didn't stall either which is a kinda good thing in my book. I plan to pull the spark plug and hope it's still there in 1 piece. What do you guys think happened?

 

That coil didn't just break, the spark plug blew out of the cylinder head and forced the coil out when it did.

Most or all of the threads will be missing from the plug hole. You will need either a spark plug thread repair or cylinder head replacement.

 

Yea I kinda figured. That must mean there was alot of pressure in the cylinder or the spark plug was loose and blew out. I Googled "spark plug blow out" and it's common on fords. Nothing about hondas. I need to diagnose the engine later today. I rather replace the 209,xxx mile motor then take off the head for a spark plug thread fix. A decent low mileage engine for these cars run $400-600 usd. Not too bad. My s2000 engine cost $3000.

 

This. Not the other. It's actually not unheard of on some other Hondas too, but not nearly to the extent some other manufacturers have the issue.

I believe there are a few threads about it in this forum.

 

The smell of gasoline when first starting the engine is a tip-off that you've got a loose plug. By any chance, did you smell gas at start-up before this happened?

 

I really hope that the plug was just loose and blew out. Hope that means I can just put in a new plug and coil and call it a close call. I'm already looking for engines and clutches to expect the worst case scenario.

I didnt notice any gas smell when driving. I was driving on the highway for a good 10 mins before the car acted up.

 

it was probably leaking for a while (caused deterioration of the boot)

 

Or the smell of raw exhaust.

 

Updated.

Any advice where I can buy a set of coil packs is greatly appreciated.

 

Visit rockauto.com and get the Hitachi OEM coilpacks, part number ends in 0053. Don't cheap out and get the Beck-Arnleys or anything similar - the stories given here is that they don't last. Last I checked, the Hitachis were right around $200 a set with shipping.

 

Take a spark plug out of a good cylinder and see if it will thread into the bad cylinder.
I bet it will just spin endlessly.

 

I hope it doesn't spin endlessly. 1 of my other plugs wasn't on tight either which makes me believe that I didn't tighten the plugs enough. When my new plugs get here, I'm going to torque them down. All I can do now is hope

 

+1 on the Hitachi ignition coils. Those are the ones to get

 

For your sanity, you might want to pick up a 3/8" torque wrench and make sure all your spark plugs are torqued to 10-15ft/lbs.

 

I do have a torque wrench. Just never had a problem with spark plugs blowing out till now. I guess I will need to check my other cars too.

 

I had the same thing happen on my 2008 GD3 a few months ago (~150k miles), and had used a torque wrench. I've seen several folks reporting it on the facebook fit forum as well...seems to be a trend. I used the helicoil repair kit.

 

I went with the Hitachi coil as well. At the time, Amazon had the best price.

 

Thanks for the tip guys. Just giving another update. Just put in all new oem plugs. Waiting for the new coil pack coming in tomorrow

 

Update!

Put in new plugs just fine and coil pack. Started right up and it's running fine. I think I dodged a close one. Lesson learn, torque your plugs!

 

Have you had any more issues with this? How many more miles on the car?