Engine revs by itself on neutral ?!
 

Hey guys (again),
It seems my car is doing something strange, so I'll need your advice :)

I was driving normally and today I noticed something weird. Let's say I'm on 3rd gear, and then I put neutral and slow down. The revs are falling to normal RPMs but then it's going to 1.5k or something, by itself. If the car stops moving, the revs are back to normal RPM again. I recently had oil and oil filter changed and Porsche said its a well maintained car. Also, there is no engine light or error code and my gas is always 100 Octane.

EDIT: It only happens if the car is moving with neutral. If it stops, the revs are falling to normal


Any ideas ?
Thanks

What year is the car?

Boxster 986 2003

Well, stop wasting your money on 100 octane.

Why are you coasting at speed?

Make sure your floor mat is not infringing on your gas pedel. Probably something more complex like TPS or MAF Sensor.

True I wa s about to start using 98. Anyway, is there anything I can do to troubleshoot it ?

You only need 91-93 octane. Are you in the USA? Include your location in your screen name/avatar. Find a quality Porsche specific indy shop in your area for help. Don't go to the dealership.

I'm in EU. Thanks for the input. So what do you think the cause is, for the high rev?

I think you need to post your location, and seek/ask for a recommendation for a Porsche specific indy shop to help your repair. You can also cross post on the 986 Forum at Rennlist.com and Renntech.org. Good luck.

Thanks guys. After all it was an AOS issue. I had it changed on Official Dealer for 145 Euros. Just in case anyone else had White smoke on startup and Engine light and auto-Revs. ;)

You said earlier there was no light. Now you say you had a CEL.:confused:

You also NEVER told us you had white smoke (which does NOT alway mean AOS).:confused:

Glad you're fixed.:)

Yeah I know, that's because I got smoke and light the next day I started the car! And I went to the Dealer immediately so I had no time. Thank God it was the AOS, even though it scared me a bit

Had the same thing happening on my '00 S where after driving it would rev higher during Idle.

Replaced the MAF and the idle was much better and also had more consistent pull at high rpm.

Glad you got yours taken care of just posting incase someone has similar issue in future.

Oh, and 145 euros ($169) for the AOS repair sounds pretty cheap. I hear its a messy job.