spark plugs defective after ±3000 km ?

[Ziggy]

I fixed a very weird problem today. The engine has been running perfectly but suddenly began misfiring and hesitating when accelerating from idle. Also sometimes it would idle perfectly for a while, the next time it could barely idle at all. I changed ignition wires, coil, checked everything but could find nothing (everything is brand new...)
It was an ignition problem for sure, so eventually I decided to change the spark plugs.
That seemed to be the problem, but...
The spark plugs (ngk bp7es) were only about 3 months old[:0] the gap had not changed, the color was right and they just look new.
What could be the problem ? I am thinking it must be something with the internal resistance of the spark plugs?
 :?:

[Richard Madison]

I'm no techie but these are fairly high compression engines and driving moderately can result in fouling...rough idle, rough acceleration, etc.

I'm in New York City and do a fair amount of slow driving.

A run at moderately high rpm for 5 or 10 minutes might clean up the gunk.

When Ole Beige is getting rough, I take her out on a highway at about 50 mph but leave it in 3rd gear so it revs near 4000 rpm for a while...does wonders. Maybe this is all you need???

Richard M, NYC

[Ziggy]

They weren't fouled. I decreased the gap to about 0,7mm and put them back in, there was still some misfiring now and then, but a lot less. Perhaps it has something to do with this hotter cam: http://index.php?topic=9274

[Ulfi]

A little "Italian Tuning" also does the trick for me - and it's great fun too!!

[hill]

Aren't  BP7es the coldest plug in that range?

[ja17]

Hello,

Yes, Darryl is correct, in most cases we are using BP5es or BP6es are used in these engines.