I recently hit 100k miles so I figured it was time for some much needed maintenance that I had been putting off. My friend and I picked up some spark plugs and he got under the hood and I heard a "what the ****?! Is that the spark plug..." This was then followed by hysterical laughter. Come to find out... The leading rear spark plug wire wasn't connected to the spark plug at all... It was just dangling! After we got the plug out we checked it out and all of the corrosion on the terminal tells me that its been unhooked for some time.

The weird thing is... I would never get a constant CEL. I would get a misfire from time to time, but never a CEL that would stay on. What did this do to my engine?! Would this mean I have excessive carbon buildup?

After installing the new plugs, new air filter and fueling up with a tank of premium I took it out on the road and it was running like new. I really really hope that unplugged spark plug didn't leave my engine a mess... Can anyone tell me what this may have done?

 

It may have pulled the wire off when I pulled a stick out from under my car which happened probably 5k miles ago. I felt a slight loss of power, but I just thought that I needed new spark plugs. I guess I needed all 4 to be firing

 

leading or trailing ? there is a difference.

but either way. yes you will have a lot of carbon.

no biggie, put new plugs,wires and coils on, drive it hard for a while. thats all.

 

It was the the rear, lower (leading) spark plug.

But yeah I took it for a nice drive last night and this morning and I'll continue to thrash it around for a bit. Nice excuse to have some fun!

 

I drove around with a bad contact for about a year. Don't sweat it, it isn't the end of the world. It is amazing how well the car runs that way though isn't it?

 

Or should say

its amazing that some cars with all proper maintenance and stuff still fails isn't it ?