Pulled the +4's a few months back after over 100k. They were fine. Replaced them with Bosche single electrodes. No change in performance, gas mileage. No reason to pull them. If it ain't broke, don't break it.

 

If ash deposits get that excessive in short mileage,ur valve guides may be worn.

 

Maybe one of the only 2 in america, allow me to quote myself from above "I ran 1 set of +4's for almost 2 years in my '98 and not one of them turned out like that. I would vote that something else is the culprit. in other words, I don't think it's the plugs fault."

 

this is an old old thread - that may very well be the case that the plugs were not at fault....

I have not reshimmed my valves yet even though Im at 256,000+, my timing was idiotically advanced from someone who owned the vehicle long before me, so detonation could have been a problem and me not hearing it over the system, on those plugs my O2 sensor died, and I was giving it injector cleaner like it was going out of style....

but even still there is one thing that bothers me about the bosche 4+...look how small that platinum electrode is! It was never really big to begin with and they have completely eroded into the ceramic insulator. For that reason alone I like my denso double platinums more - they have a BIG blocky platinum electrode that will take forever and a day to erode...lol

I think im going insane...lol maybe its just the chick im seeing right now...

 

Marry her...that'll take care of that!





Oops! Did I really say that?