John Etnier

Anyone care to take on this phenomenon? For some time now I've been experiencing increasing Check Engine Light occurrences traceable to the two knock sensors. When lit you could feel the engine responding poorly to detonation conditions.

And then I started getting a strong buzzy rattle from the area in front of the driver at foot level, when letting out the clutch in first. It would shake the floorboard, but could not be detected from outside of the passenger compartment. My mechanic and I spent a lot of time trying to figure out what was causing it but couldn't. (There was a bright, metallic rattle in a resonator located in the middle of the car (RSBarn exhaust), but this rattle was much lower and could be felt in the the pedal.) The firewall is intact.

And then both symptoms disappeared. Just gone. I don't know about the resonator: have to get lift time. But the CEL hasn't fired in a week, and the clutch-pedal rattle is gone.

I have knock sensors on hand here now but my mechanic doesn't want to put them in until we have a better idea of what's going on.

Ideas?

PorscheG96

Is your cam timing sensor crumbling apart?

John Etnier

Good question- will check: Hall-effect sensor, right?

PorscheG96

Yes, it's adjacent to the HCV right above the header. They're all disintegrating by now which could trigger CEL and possibly throw timing off enough to engage the knock sensors...