gavin lewis

I have a 2005 997, with VF Engineering Supercharger, and it's been getting a throttle / idle problem when warm. No codes yet, I have Durametric Pro. It will be driving fine, and then the idle will dip, the ECU will try to catch it, and it will eventually die after a second or two. It also will have the throttle pedal not respond during these moments. Otherwise it drives fine. So far I've pulled the TB and opened up the electronics and sprayed out with contact cleaner, and pull the MAF and cleaned it, now it's getting ready to start getting expensive. I've read the threads on here about throttle pedal response and none of them reflect the idle dying out. Anyone who's dealt with this that can help would be greatly appreciated before I start throwing money at it. Edit, it's a 997 S, with the 3.8, I doubt that's relevant, but better safe than sorry.

Petza914

Replace the switch on the brake pedal - yes, I'm serious. You can simulate what I'm talking about by driving along and with your right foot on the gas, use your left foot to press on the brake and see if it feels like the same thing that's been happening to you. If so, it's the little button switch that is on the brake pedal. Turn 90 degrees to remove and replace with a new one.

gavin lewis

Will that switch cause erratic idle too? I disregarded it from other threads because no one seemed to have the idle problem I'm having. I ordered a MAF because I unplugged mine and the idle didn't change, so I'm thinking it's failing if not done, and I ordered a smoke generator because I'm pretty sure I have a vacuum / boost leak. More to follow, and thanks for the feedback, love your RUF.

Petza914

No, the idle problem is something else. The brake switch just shuts down the power when you're trying to accelerate for safety so you don't have a car with the throttle pinned that you can't stop.

If you haven't replaced your throttle body, that would be the next culprit after the MAF.

Thanks for the compliment.

Bruce In Philly

2009 C2S 156K miles

I had that brake switch fail (a plunger type) on my 2000 Boxster... same (or similar) system. My problem was I started stalling from a dead stop... I thought I was losing my touch with the clutch. On a whim, I took the car to the dealer who hooked up the Porsche computer... right away, the system said their was a fault with the switch, and little drawing of the switch came up on his screen. No dash light. The tech thought it may be interfering with the stability management system cutting the throttle... getting confusing signals.... but he really didn't know... no Porsche training on this issue.

Anywho, we swapped out both the clutch and brake switch... different part numbers and colors.... but same type of switch at the pedal. I took the switch home, and pulled it apart... sure enough, the flat copper "brush" had a hole worn through it.

Now with my 911 with 156K miles on it.... I occasionally think of swapping them out just as preventative maintenance... but is sure seems Porsche improved these items on my car... so I think I will wait... more entertainment that way.

FWIW....

Peace
Bruce in Philly

Petza914

Bruce, nice work on the switch post mortem. I should have done that to confirm that was my issue, but the problem never returned so I assume that was it. Actually happened to both my 05s. Would start to pull away from a stop and the car would just fall flat on its face for a second, that felt like a minute, then it would take off again and be fine. Sometimes it would cutout when underway too, but that was usually less pronounced.