Spark plug electrode bent (twice)

2002 Nissan Sentra SE-R, bought used in 2007, with rebuilt engine installed.

Daughter owns it, and she lives in another state.

About 2 years ago, during interstate driving, the car started missing badly. She pulled off at a rest area, waited a while, then restarted the car. It ran OK until she got home. CEL was lit, but the missing stopped. Took it to her local mechanic and found that one spark plug electrode was badly bent. Replaced the plug, ran fine.

Fast forward to yesterday.

Driving on the same interstate, and the car started missing badly, and CEL was flashing. She was near an exit, so pulled off, got towed to a Nissan dealer, and drove home in a rental they provided for her. Got the call this morning that one spark plug electrode was badly bent. They replaced that plug, and she is now driving home. This time she knows it was the #4 cylinder. (She doesn't know which one it was the first time, but will try to see if her mechanic has a record of it.)

Any clue what could be causing this? It seems like if there was a mechanical interference problem, it would happen right away.

Thanks!

Craig

Reply to
Williams
Loading thread data ...

I don't know, but I'd stick a borescope down in there and take a look around. Maybe some ceramic insulator fragment floating around in there?

--scott

Reply to
Scott Dorsey

Or lots of carbon, although that would be odd on a "rebuilt engine" - unless something isn't hooked up right causing excessive carbon buildup?

nate

Reply to
Nate Nagel

Better have what ever belt-chain-gear turns the cam or cams checked out. also, read this:

formatting link

Reply to
Paul in Houston TX

as you say, if it were interference, you would expect it to be an issue right away.

if she can bring the damaged plug home and you can post a pic, that would help considerably. because "badly bent" would most likely preclude the plug firing normally after a re-start. however, something like this wouldn't.

bad pic angle, but you can see the center electrode is touching the ground electrode. somehow it had come loose in the plug so that sometimes it would touch, sometimes it wouldn't.

same plug held inverted. it ran normally sometimes, misfired others.

i would investigate and use only a reliable plug like ngk.

Reply to
jim beam

Better have what ever belt-chain-gear turns the cam or cams checked out. also, read this:

formatting link
Paul,

Thanks for the link. Another post in the Nissan Help forum suggested the same thing. And the car does have higher than normal oil consumption.

Craig

Reply to
Williams

The symptoms remind me of boyfriend driver syndrome, but it seems the model is plagued with manufacturer issues:

formatting link
-----

- gpsman

Reply to
gpsman

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.