Porsche 911UK Forum

Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.

Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.

Replacing Oxygen sensor


Well-known member
18 Apr 2004
Hi all,

I've got a problem with my idle speed. It's slightly high (at least I think it is..I've only had the car a month) at 850-900 and occasionally it creeps up to 1200 or so for a few secs and then drops back. Also after a run it hangs up sometimes.

I took it to Northway Porsche specialists who reckoned that the Idle Stabiliser Valve was shot..I took it out cleaned it - no good, then bought one and replaced it. But it hasn't changed, although I keep thinking it has but I think that's my brain trying to soften the blow.

I've read a few places that the Oxygen sensor plays a part in all this and could do with being replaced.

Could someone please help me and tell me a)how to find it?! , b)what it does and c)if I'm on the right track.

Thanks, Don.

Migration info. Legacy thread was 15139

I'm presuming you have a 911, since you didn't say, but on my 993 if you look under the rear of the car (in the middle) you'll see 2 wires connecting to a sensor bolted into the exhaust. Thats the oxygen sensor.

Its job is to monitor the unburnt oxygen within the exhaust system and modify the timing accordingly.

Never replaced one myself, but I imagine they are quite difficult to remove given the constant heating and cooling it gets from the exhaust. Might me able to remove it if you apply some heat with a blow torch first.


<SCRIPT language=javascript>postamble();


Migration info. Legacy thread was 15142
Thanks Paul,

Yes, sorry, it is a 993 (1996). I was a bit tired when I wrote the message and hence forgot the most important part!

Do you think that replacing it might help my problem? And do you or anyone else for that matter reckon it's a job that a DIY beginner could accomplish.

Thanks again,


Migration info. Legacy thread was 15143

Not exclusive to Porsches, but I've read that these things do have a tendancy to fail and can give the type of issues you wrote about. So I'd think its worth a go, but all depends on how much it is. Had an Air Mass Meter (Similar sensor) go recently on my BMW which made the engine hesitate at around 3,000 RPM affecting the performance. Luckily it was under warranty, but the part would have cost me £130.

If your going to have a go at removing it, see if you can loosen it with a spanner first and if that doesn't work , then get the engine (and exhaust) nice and hot and then try again, taking care not to burn yourself. If you manage to loosen it then go and buy a new one, if not my advice would be to get someone else to replace it. Better that they break it off from the exhaust then you doing it and having to replace the exhaust.

Good luck



Migration info. Legacy thread was 15154
Thanks again John,
Sorry to harp on about this, but what exactly should my car be idling at?
I might try and see if I can take the O2 sensor out when I'm feeling brave.


Migration info. Legacy thread was 15157
Sorry Paul, don't know why I called you John!


Migration info. Legacy thread was 15158
Mine idles at about 800-900.

Migration info. Legacy thread was 15162

New Threads

Forum statistics

Latest member