Patton250

So since I had bought this turbo S a couple of months ago I’ve done several things to it. I added Akrapovic L Pipes and Akrapovic catback exhaust and I’ve done a stage 2 tune. Since then I’ve noticed a couple of things that I don’t remember happening before.

1. Sometimes the car idles at 850 RPM and sometimes an idols at 1000 RPM. Once it decides where it’s going to idle it stays there. It doesn’t matter if I’m in normal or sport mode. I thought it did matter what mode I was in at first because normally in normal mode it idols at 850 RPM but I noticed it idling in normal mode at 1000 RPM today. I don’t know if any of this is a big deal or not but some of you might know.
2. Sometimes when stopped at a red light or even in park the car shimmies back-and-forth from the engine area. I mean literally a half inch to the left and right continuously. I can watch the water in my water bottle sway back-and-forth while it’s happening. When this is happening the RPM stays steady and is not fluctuating. It happens in normal mode and in sport or sport plus mode. It does not happen every time I stop at a red light. It does not do this when driving or at least I don’t notice it. The car still drives extremely normal like it did before and I noticed zero problems throughout the gear range.

Please don’t think I’m paranoid but this is my first Porsche so I just have these basic questions. Let me know your thoughts on these two things. Do either of these things happen to your 992 Turbos S’s?

Patton250

Vacuum leak? Bad gas?

rk-d

Vacuum leak can cause bad vibes and weird idle. I’ve run into that in my 993. I’d think the 992 would trigger a warning if that was the case here.

Bad motor mounts can cause weird shimmies - the dynamic engine mounts are known to fail sometimes. That said - it should trigger a warning if that’s the case. The exhaust tips (hidden behind the fascia) would be moving around and/or drooping if this was the case.

My car has a solid idle and no shimmies, for what it’s worth.

Good luck. You car is too young for this to be carbon build up - you could always try some fresh gas and an Italian tune up?

Patton250

I don’t know what an Italian tuneup is. Lol :-)

The part that’s weird is it doesn’t shimmy all the time. No lights come on either. The car drives great after taking off. The only thing I can think of is bad gas other than the other things I talked about. I filled up at a race track and then 10 miles later pulling up to a red light it did it for the first time. I was just about on empty when I filled up. I was also driving the car pretty aggressive after that fill up so even though I only went like 10 miles it definitely was using that new gas before I came to a red light and I noticed it the first time. Maybe I’m overreacting and just need to go through another tank of gas. I just don’t want to hurt the car. Coincidentally I didn’t start doing this until I installed the exhaust system and upgraded to stage two on my tune. But like I said I didn’t do any of that until after I filled up.

rk-d

I was mostly joking. An Italian tune up is basically driving the ever loving sh*t out of the car.

Bad gas is certainly a possibility. Have you checked for any codes? I’m not that much help - maybe you can touch base with whoever made the tune and see if they have any ideas.

Patton250

I did run logs with the tuner but they didn’t see anything. Of course we weren’t checking idling. If it doesn’t go away with the new new gas I’ll remove the tune and bring it to Porsche to diagnose.

ss2z06

Not sure about the shimmy but does the rpm idle change have to do with the a/c on or off? Many cars raise the idle a bit with the a/c on.

M-AlTerkait

Make sure your fuel cap is fully secured and not leaking.

Patton250

that’s a great point. I mean I’m in Florida so the AC is always on but yesterday I put it on Max AC a couple of times. I’ll check that out today. Great suggestion.

Its basically just 1/4 of a turn and then it locks in place. Are you doing doing anything different?

Patton250

I can’t stress enough at this one point that might help somebody you guys who really know how to troubleshoot mechanical issues with these 992’s. When it’s shimming back-and-forth from the rear end of the car it does not affect the rpm at all. The RPMs stay steady at 8:50 and sounds perfect. It’s as if a man we’re standing in the back of the car with his hands on the fenders above the rear wheels and was just pushing the car and releasing it; push release, push release, push release. Not a very hard push either just a shimmy. Lol. About a 1/4” back and forth. I’m going to go for a ride today and see if the new gas changes anything and if it doesn’t the next thing I’ll try is removing the tune. However I’m not a betting man but if I was I would say removing the tune wont do anything. It’s either going to be bad gas or some sort of engine thing like a vacuum leak or something. Maybe when I was having the exhaust installed they knock something out of whack. Who knows. That’s why I’m hoping someone here might have an idea. I guarantee we have at least a handful of bad *** mechanics that hang around here. I hope one reads this thread.

hcvone

My idle is 900 is sport and sport plus, probably 600-650 in normal, which it never gets driven in that mode, but it's not always 900, some times 900-1000. Not sure about your "shimmy" issue, maybe a gator or big snake crawled up under the car JK.

rk-d

Catback shouldn't affect much unless they somehow screwed up the O2 sensor -- which should generate a code.

Not a bad idea flashing to stock - if anything this would eliminate that variable.

Do you see the exhaust tips moving back and forth or side to side?

Patton250

Honestly I’m always at a red light in the driver seat when it happens and it only happens for like 3-5 seconds and then goes back to normal. So I don’t know how I could get outside and see it. I am going to remove the tune and return to stock. But like I said I would bet a considerable amount of money that the tune has nothing to do with this. I don’t see how it could. As little as I know about these things it just seems impossible that could cause anything like this. We will find out though. :-) I just exercised and have to cool off and get cleaned up and then I’ll flash it and go for a ride. I need to do it this morning before the rains come.

sechsgang

before you take it to a porsche dealer, ABSOLUTELY put it back to stock. This will already be iffy as if there's an issue, they will check boost readings and see they've been higher and they can void your powertrain warranty. Wouldn't given them any extra hints.

NigelPlays

Your Ac is on full blast with seats ventilated is my guess.