john981

Compared to my other cars, I have noticed that my base 981 Boxster dosn't run as smooth as I am used too. When staying still my rpm gauge swings between about 650-700/730 while in my other car the rpm gauge is pretty still on one number. Do you see that on your cars? Is this normal or is there anything wrong with the engine?

Thanks in advance.

Pep!RRRR

Marine Blue

Dom991.1

LexVan

Mileage?
Maintenance history?
Location?
Fuel?
Any changes with AC on or off?

Need more info.

Marine Blue

ChicagoSpeed996

Sounds normal, mine isn't rock steady either, I have the 3.4S.

TMc993

My 981 base with 39K miles on it grumbles and hunts a little on cold start-up, but steadies up as it warms up.

If you haven't tried it, a long, spirited run with high revs might help, but the traditional full-throttle "Italian tune-up" is not really as effective with today's electronic engine management as it is/was with older cars with less electronic management.

As LexVan implied, I'd be looking at service records and see if you're close to, or past, some essential service like plugs, air filters, etc. Also, things like fouled injectors and faulty ignition coils come to mind, but I'd check the other stuff first.

MyNameIdeasWereT

Inconsistent RPMS at idle can be caused by a bunch of things, but I would always start with cleaning the MAF and throttle body.
An overly dirty air filter can cause similar problems.

Spark plug gap could be too far off, which often will not throw a code for misfiring.

Could be bad or inadequate fuel.

If the cats are clogged or burnt out, the car will start to adapt its fueling based on what the O2 sensors read.
Could even be damage to the O2 sensors.

There's a number of other things, but it's always worth starting with the free stuff (cleaning) and the standard maintenance.

My 3.4S has 38k miles and idles perfectly smooth once up to temperature.

PorscheAddict

Sounds normal to me. Mine has never idled as steady as an eco car.

john981

Here some answers to the asked questions:

- Car has about 54k miles
- Is located in Southern California
- All services are done on time, the 40k service was done about 10k miles ago so assume the air filter is still pretty clean.
- As I did the PPI everything was fine. My mechanic even took out one of the spark plugs and everything was in order.
- I always put premium gas, dont know about the previous owner.
- I think the last owner drove lots of short trips. The board computer showed in the last 8k miles average 20mph. I assume lots of carbon build ups.
- The gas mileage is pretty poor, I average 20mpg. My last 981 was much better. I assume has also something to do with the carbon build ups.
- Didn't have the chance to drive it today o bring it up to temperature to test how it behaves in Sport mode but will do as soon as I have the chance.
- cleaning the MAF and throttle body was suggested. How can I do that?
- Italian tune up is something I had planed anyway, will do as soon as I have the opportunity.


Any other tips and thoughts would be highly appreciated.

thanks
John

A432

There are some people who didn't do the plugs at the 40k, do you have a receipt for them being changed?
If not, potentially plugs/cracked coils, I'd do those if any question, most likely culprit mileage/uneven idle and should be done anyway.

Dom991.1

MyNameIdeasWereT

Over time, dirt inevitably starts to build up on the MAF. Only use MAF cleaner spray and never touch it directly by hand or with a cloth. Always remove the MAF before cleaning, so you're not spraying the cleaner into your intake.
I'm not sure why Porsche would be any different, but with every other car I have owned and worked on, the MAF should be cleaned on an annual basis, if not more frequently. Especially in dusty or humid climates.

The throttle body should also be removed and cleaned annually. If not for cleaning, at least for checking for any build up. There's also a spray cleaner you can get for cleaning the throttle body, though I strong encourage removing the throttle body before cleaning too, so the cleaner doesn't run into the engine.

MatthewinGA