My break in was by the book. No revs over 4000 RPM for the first 2000 miles.

I noticed something interesting yesterday - The outside temperatures were over 100 deg F and the stumble seemed almost non-existent. I think it's definitely a sensor issue. I've noticed changes in the stumble with temperature and humidity.

So far I've noticed that a dry 60 deg F day is also good for less apparent stumble. Now it seems like a humid 100 def F day is also good. Will continue to collect data points...

 

Hey folks. Is this issue pretty easy to observe? I am in the market for a pre-owned C2S and I've driven several and not observed the behavior.

I'm starting to zero in on a car and will obviously drive it to rule out this issue....had similar unsolvable, "not-an-issue, they all do that" issues on my previous BMW, and don't need it again. Reading through the thread, it seems maybe the easiest way is to set the cruise at a speed that will yield the 2500 rpm, or thereabouts. Is that the best way? Or is it better to hold steady throttle say every 100 rpm from 2500 to 3000 and see? Or just accelerate normally?

Thanks guys. Love forums to sniff out issues like these!

 

Suggestion: Start at 1500 RPM in 4th gear on a slight uphill section and apply slight but steady throttle so you'll slowly accelerate through the RPM band up to 4k. That's how any stumble should manifest itself. If you suspect a specific range let the RPM drop just below and start over.

 

That's not a good suggestion. You are lugging the engine by doing that. It's not good to do that in any car.

 

Then don't do it. We both live in free countries.

 

1500 may be a tad low, but a smooth acceleration from 2000 rpm is definitely not an issue. The stumble in my car is very easy to reproduce; either a smooth acceleration through ~2500 rpm in 2nd gear and up, or on a long hill with the rpm held near 2500.

 

My 911 had a little bit of this but got better as it got broken-in. But I sold it anyway. Not much if any mention of this in the 981 forums, but I just got rid of my 2014 Boxster S (3.4) because it also had this stumble and the dealer said "they all do that". Well, there were other issues too, but the stumble really knocked down the fun factor of driving the car, and since I had bought the thing used at a pretty good price, it didn't hurt me to get rid of it last month.

 

My stumble is alive and well.

 

Interesting dealer answer as I basically got the same. At which RPM and vehicle speeds did the stumble occur in each vehicle? I still have a nagging feeling it was artificially built in to pass European noise emission testing (which are done at exactly 50kph at full throttle).

 

My 2016 Cayman S, purchased new this July, has had the same problem from day one. The dealer, the regional rep, and Porsche NA all say this is normal, and Porsche will not do a thing for me. This car was meant to be mainly a daily driver, so I get a daily reminder of this lousy drivability. I don't believe for a minute any automobile company the world would release a car that drives this badly for production. The treatment from Porsche customer service will prevent me from buying any more Porsches. And you can bet I am telling everyone I know about their treatment.

 

Just put a new throttle body in. $1k installed at the dealer. It sucks that they won't cover it but it's not worth going too crazy over.

 

If they contend that the stumble is normal, have them check this forum (and 6SpeedOnline) and see that most owners are, in fact, stumble free. Best guess is that the stumble only affects about 10-20% of owners.

Remains a mystery as to why Porsche refuses to address the issue. Greed, arrogance, stupidity, who knows?

 

Replace the throttle body on a brand new car?

 

My 2012 C2S has no stumble whatever, nor does my friends '14 S Cab, so my guess is that if you feel a stumble, something is wrong, and if you don't its not.

 

I'm sorry to hear that.

My used 2014 Boxster S also had this issue. After living with it for 7 months, and a trip to the dealer ("they all do that") I gave up and sold it.