Re: 2006 987 S idle Rpm,s Fluctuating a lil,what could it be?

My totally stock Boxster with 110,000 kilometers (65kmiles) now has a slight fluctuation in rpm at idle,maybe a 100 rpm than was never there before,the needle was dead solid.
Is this normal or an indication that somethings going out off adjustment,maybe MAFneed cleaning or throttle body .I have no cheak engine lights and otherwise runs good.
What r your thoughts,leave it till it get possibley worse or do some preventative maintenance.

Quote
moresquirt
My totally stock Boxster with 110,000 kilometers (65kmiles) now has a slight fluctuation in rpm at idle,maybe a 100 rpm than was never there before,the needle was dead solid.
Is this normal or an indication that somethings going out off adjustment,maybe MAFneed cleaning or throttle body .I have no cheak engine lights and otherwise runs good.
What r your thoughts,leave it till it get possibley worse or do some preventative maintenance.

J/K!

My WAG is the AOS is starting to go out.

The 1st bum AOS on my 2002 started with the symptom of a mildly hunting idle and a bit of a stumble off idle when taking off.

A functioning stock air filter system won't allow the MAF to get dirty.

You can check the throttle body. If it is "dirty", oily, and if there is a bit of oil at where the hose from the AOS connects to the intake manifold, that's another sign the AOS is going bad.

Clean the throttle body.... that was the sole issue of my bouncy, irregular idle .... 2000 S.

Peace
Bruce In Philly

That may or may not fix it but it's a prime suspect and it's easy to do.

... not so much so with the e-gas engines where the DME controls the throttle body, although cleaning stuff usually is a good thing.
I would first check the vacuum system.
Either a bad AOS as MarcW guesses or a broken or disconnected vacuum line, vacuum check valve or similar.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

causing uneven flow past the flap and the car compensation isn't as fast to react as the turbulence affects changes the airflow.

... for cleaning the throttle body.

[pedrosgarage.com]

Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

thx,stock air filter new 10,000 miles ago and paved roads only so u r prob correct on Maf .Its the original AOS but will cheak Vac lines first.If AOS is starting to go is there another tell tale sign
other than idle fluctuations thx

... if you're lucky it will hoot like an owl, but not always.
Sometimes the tear in the diaphragm is quick and big and you'll get a lot of smoke, but most of the time it really won't show obvious symptoms until it really goes.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

several years ago I recall a poster with the same symptoms.

As I recall, it was an issue with the climate control and its interface with the computer.

It might be found if you search - or someone with a better memory might be able to tell chapter and verse.

I just pulled the throttle body out and have a few questions,firstly this is a 2006 S so slightly different than the 986 on some stuff per pics in do it yourself section.When i pulled the rear or large hose section u call a T i think (but not a T on Mine) its a seperate 4" line from the Throttle body Hose .
closest to the rear seats out,it pulled a small hose off with it underneath maybe 1/8" plastic line,the only place i can see that it may have come from is the hose that comes off the top off the power steering fluid,looks like it may slide up inside that line
but not sure why would there be a hose coming off the power steering unit unless its a vent line or overflow,can u confirm that i connect into that on re assembly .Also the plastic line coming off the AOS is pretty oily,does that mean the AOS
is going,should that hose be dry or is that typical ,oil is not dripping out though. thx.

The small hard line is a vacuum line and it goes into the rubber sleeve between the tee and the intake plenum.
The AOS line doesn't always seal properly and may leak oil. That's not uncommon.
The hose is intended to pass "dirty" air into the engine combustion chambers to be burnt up.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Pedro,Sorry for my lack off experience but i am not sure i understand.When i pulled the front 4" hose to remove the throttle body i had to disconnect a small 1/8" vac line.When i pulled the rear 4"hose
a small 1/8" vac line came out from under the intake Plenum on the power steering side.I looked under there with a mirror and i see a 3 way Tee off vac lines but there all connected,it would have to be a 4 way to
attach this line.Sorry but im missing something,should i send a pic?

... I'm sure there's another single line from where it got disconnected.
Happy Porschen,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna