First off, I may well be paranoid, but here goes...

I had the rear trunk open today while the car was idling, and I heard a hissing noise coming from the oil filler tube. The cap wasn't screwed on tight enough, and when I tightened it, the hissing went away.

Now I got curious and removed the cap completely while the car was idling. There was quite a bit of suction at the oil filler tube, and the car's idle became irregular with the cap off -- is that to be expected?? I don't think I remember my 951 being affected by the oil filler cap being on or off...

Anyone want to tell me that this is perfectly all right so I can go to sleep?

Thanks,
Gary

 

This is normal. With the cap off you have a massive air leak and the DME is trying to adjust to it, which is why the idle is off. You can also get a check engine light.

 

Thanks!!

Gary