CJFusco

I have an interesting issue in my 2007 Cayman S with 67k miles. The car has a surging idle when warm, which extends to on-throttle behavior: when one’s foot holds the throttle steady at what should be 3K RPM, the engine surges rhythmically between 2K and 3K.

I saw recently that one of the coil packs was starting to crack, so I replaced coil packs and plugs preventatively, with fingers crossed that it would cure the surging RPM issue, but no dice.

I’m suspecting either a vacuum leak somewhere, throttle sensor, or possibly MAF sensor? Any thoughts?

CJFusco

Bump. Has anyone encountered this issue before?

CJFusco

UPDATE! Even though this has gotten zero responses, it might help others down the road.

I plugged in my tuning software, and found one code: 1095, which is “mass air flow ahead of throttle vale implausible (too high)”. Now, the car does have an IPD plenum and 997 GT3 throttle body, but it’s running a tune to adjust airflow and has been doing so for several years with no issue.

On visual inspection, I did find that one of the hoses running from the the AOS to the TB was maybe a little loose, and also had some oily residue around it. Pulling that hose, it looks like there is a little bit of oil in the hose. I disconnected the hose from the AOS itself, and there was more oil at that end. See attached pics.

So: follow-up questions: 1) might this loose hose (if it was indeed loose) have caused that idle surge and error code? And 2) is the oily residue a warning sign that my AOS is beginning to fail?