I did an oil change today and cleaned the plugs. What i found after 5K kms of driving was kinda disturbing.

The Leading plugs had a slight brown deposit on them, dry not too thick.

The trailing plugs had thick black deposits (carbon?), kinda wet.

This is after the car sat overnight so it might be oil in the chamber but i dont think it should have that much deposits on it, almost 1mm in thickness!

Is this normal?

 

From what i've heard the trailing dont do much anyway, just for emissions... as to whats causing it, maybe youre running really really rich? Have you checked your tps recently? maybe try an a/f guage..


~Jesse