Hello- I have a 2002 SC430 with around 160,000 miles, daily driver.
Here is my dilemma:
It started about two weeks ago.
I started feeling some hesitation when accelerating from a dead stop. Once moving the car was great, smooth.
A few days went by and my check engine light came on...the code was P0161 (O2 sensor heated circuit Bank 2 Sensor 2) in other words Down stream passenger side.
Replaced it and the CEL went away, but now I have the same hesitation and now what sounds like a back fire/detonation.
Drove for a few days same symptoms, no CEL came on.
Decided to do a tune up- new spark plugs, clean MAF and throttle body and new air filter.
I removed the spark plug in cylinder #2 and it looked good, put in the new one.
HERE is where I freaked out, as I started to remove the spark plug in cylinder #4 I felt the plug was very loose, took it out and NO ELECTRODE.
The electrode was sheered completely off in the engine... what kind of damage could I be looking at?
What should I do next? should I remove the valve covers to search for the electrode?
Any assistance will help me sleep tonight or not.
Thank you

 

I cringed when I read this post. Couple of questions: 1) Did you install the current plugs? And if you did, did you torque right? 2) What kind of plugs are they, NGK or Denso or other? 3) When was the last recorded plug change, miles and months?

 

Most likely it was blown out through the exhaust valve. Only way to really know for sure is to remove the head.

 

unfortunately I did install them and do not own a torque wrench.
I use NGK platinum, I changed them 2 years 8 month ago and have put about 35,000 miles on them.

 

If the electrode scored the cylinder walls you would be burning oil. Kind of a tough call. The electrode is so small I kind of doubt it's still in the cylinder. Probably stuck in cat. Removing the valve cover does not give you access. The whole head has to come off.

 

Use a borescope with a magnet attachment on it . Plus the borescope will let you see the condition of the piston crown, and cylinder walls. You can also use a mirror attachment to look at the valves. You're not going to be able to do this with those floppy eight dollar ones the plug into your phone. But good ones with attachments aren't that expensive still.

 

Agree borescope is the only way....they have ones now-a-days that connect up with your smartphone.

 

By the way, I expected it to be a Bosch plug. It seems to be more common with them.

 

Now thinking about it, these tips are exposed to high explosion pressures correct? You did not accidentally drop the a plug while you were installing them?

 

mandyfig: I don't recall if I dropped the plug when I originally installed them.

I installed the new spark plugs ( need to buy a torque wrench) and will take the car to the dealer.
I need to take care of the air bag recall so this is a great time to do it. I will have them check things out for me.

The engine sounds good, smooth, no ticking or smoke from the tail pipes.

I will report back as soon as I get the dealer results.

 

The borescope and magnetic is a good idea as well. Assuming the electrode is attracted to a magnet. I was thinking another option is firing up the car with the plug removed for a few seconds. I'm still betting its not inside the cylinder. Glad to hear things don't appear to be damaged.

 

Dealer said that they did not see any damage from the electrode.
A few of you mentioned, the electrode must have passed through the exhaust and is stuck in the catalytic converter.
Thank you for all of your help.