larrysb

Since I bought the 2011 C2S Cabrio a few months ago, it's had a somewhat unsteady idle. I've read the threads about cleaning the throttle body. I did that today. It wasn't very dirty, just a bit smudgy. I'd say the idle got a little bit more stable, or perhaps just my wishful thinking. There's some oil film further down the intake manifold, probably due to the slight overfill right before I bought the car. I did get a little cloud of smoke and the warnings right after getting it, which I corrected by changing the oil and filling it properly. It appeared to have just been changed immediately prior to my buying it. Less than 100 miles since it was changed on the service reminder and it looked perfectly clean when I drained it.

So how much idle wiggle is normal? I'm used to other cars which idle smooth as glass and don't vary much. I'm figuring this is normal for this particular engine, just a little jitter on the tach at fully warmed up idle. I'm not too worried about it, just trying to understand it since I haven't owned one of these before and have no idea what it was like new.

DC911S

larrysb

Didn't take it off - but I don't know what the TB calibration process is.

Dartmouth

I have an 09 4S cab with the same issue. Car runs great but I have that jiggle at idle. Helps to make sure you let it warm up and run for a while when you first start it up. I had the throatle body cleaned but it didn't help really. MAF replacement may be the answer but I haven't done that.

love2drive

A shaky idle might indicate a need to clean or replace idle air control valve. Hope cleaning is all it needs as it's typically not cheap.

DC911S

Try this....

https://www.6speedonline.com/forums/...tle-reset.html

or

https://rennlist.com/forums/997-foru...tle-reset.html

matthewreed1

I had this issue and it got worse and worse. It ended up being that the high pressure line for the power steering had come loose. Power steering fluid had been getting sucked into the intake, and it left an oily residue. Plus, it was idling poorly. I would reset the computer, and that would temporarily help. I didn't figure it out for a while until the power steering started making a shrieking sound indicating that it was failing. I was going to change it myself but when I took off the throttle body, the oil residue was everywhere. The air filter was also moist with that. After I took off the high pressure line screw to the power steering and put on some loctite, I sealed everything back up cleaned everything and refilled the power steering fluid. It has been better ever since.

Khloesdad

My 06 997.1 {55,000} has had a nervous idle since purchase. I bought it from a friend so I know its had OEM plugs/coils replace as routine maint. Still that idle lives on. I've just lived with it unless someone offers a solution.

Ironman88

I was thinking that Bruce in Philly might see this post and chime in - as he has commented in other posts about addressing his 997.2 idle. I believe his comment was that he was able to get it rock steady.

You may want to PM him... Bruce In Philly

Hella-Buggin'

This isn't normal. My 06 S idles as smooth as silk. The GT3, not so much but I'm told that is normal with a Mezger. Maybe you have a vacuum leak?

Khloesdad

I did the recalibration and it seems to idle perfectly normal now.

Bruce In Philly

2009 C2S 155K miles

I am no expert on bumpy idle.... but..... here is my list of things to attack it, in order, and I did them all:

1- High concentration of Techron or other injector cleaner, then run at high RPMs for a long time .... ala "Italian Tune Up with a Cocktail"
2-Clean stuff, use a can of Mass Air Sensor Cleaner spray: Remove the throttle body and spray the crap out of the thing, including shooting some spray into the pivots (you are not supposed to do this but what the heck), replace or at least clean the gasket (remove and re-seat), and spray and shake dry the mass air sensor.
3- Reset the throttle body (this never did anything for me but was cool to do nonetheless)
4-Replace the throttle body and gasket: https://rennlist.com/forums/997-foru...ttle-body.html

BTW, beside a bumpy idle, I started to get "chuggin" under acceleration..... this was the last straw so I replaced the throttle body. Worked and still is dead smooth 95% of the time...

Is this the right way to attack this problem? I dunno....

Peace
Bruce in Philly

Khloesdad

Ok so 7 days ago I did the TB recalibration. I still cant believe how smooth it idles. 8 months of ownership and I had just figured slightly rough idle was normal.
Again, thanks for the link.

larrysb

Old thread.

I wound up replacing the throttle body. Ordered from Roc Auto for around $135.00 under the Bosch part number and it came with the Porsche part number on it too. Easy to change. Got a new gasket from the stealership. Idle is smooth and throttle response is great. It's been in several months or more and doing great. The issue is wear, the butterfly was a lot sloppier in the old one than the brand new one.

PhillyNate

I was experiencing an occasional flutter awhile back. Car was running just fine tho. No issues under load or anything. As it turns out a fuel change has cured it 99.9%. I was running Sunoco 93 almost exclusively and was unaware it’s not “Top Tier” fuel. I ran a few tanks of Conoco 93 and it’s all but cured in my case. Needless to say I use nothing but Conoco now AND it’s cheaper. I can only assume it cleaned out something in the fuel system.