Fluctuating idle fixed. - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Pinarelloman · 05-07-2010, 09:30 PM

I started "The Box" yesterday and after about 15 secs idling it made a pop sound and almost stalled. After that while idling, the idle was fluctuating by about 50-100rpm and took 2-3 attempts to start the vehicle after refuelling.
After reading on here and Pedro's garage about cleaning the throttle body, I decided to try there for starters.
After reinstalling the clean throttle body, the hardest part was getting the intake air hose back on to the throttle body. As this is hard plastic a small amount of lubrication was required.
It took maybe 1.5hrs & problem solved.

Keep the self repair tips coming guys. I am new to Porsche ownership & love the car. I also hate the overpriced dealers & what they charge for simple work.

willd · 05-08-2010, 06:17 AM

Just to back up what Pinarelloman says - I'm not particularly mechanically minded, but managed to do this bit of DIY. As it happens the throttle body on mine was clean anyway so didn't fix the issue*, but it's definitely something you can do yourself. And yes, getting the hoses back on is a bit tricky, but not impossible.

*my issue with running problems turned out to be three things;

1) A faulty MAF sensor - even though it had only been changed 12 months ago.
2) The brake servo had a leak - meaning air was bring drawn back into the engine through the servo making it idle roughly.
3) Faulty pre-cat O2 sensor.

Pinarelloman · 05-12-2010, 02:33 PM

One further thing to add to this, is that there was oil in the AOS end of the tube that connects the AOS to the throttle body.
Is this normal, or is the AOS on the way out?
The vehicle does not blow any smoke & idles fine.

Steve Tinker · 05-12-2010, 03:17 PM

A little oil is not unusual, tough you should keep an eye on it.
A good guide to the state of your AOS is try taking off the oil filler cap (in the rear boot) while the engine is idling. If the cap is difficult to remove because of a vacuum, then the AOS is failing and a new one required.

Pinarelloman · 05-13-2010, 12:43 PM

Thanks Steve, yes I read that & the oil cap is easy to remove. So for now I don,t have a problem.