stealthboy

Ok, so I've been reading about the hesitation in the PDK that some are experiencing, but is anyone else getting some hesitation in their manual? I have a slight stumbling/hesitation that seems to be in the 2100 RPM area (so if I'm trying to cruise at low speeds, say 32-35mph in 3rd gear) it'll stumble just so slightly with constant throttle. Also, if I then want to accelerate immediately from that cruising speed, there is some hesitation, then a little stumble right around 3000-3100 RPM again as it climbs.

It's very slight, but it is starting to get to me. I'm almost considering taking it to the dealer to have them check it out, but I am afraid they'll just call me back after looking at and tell me they couldn't feel anything. That's always my case when there are slight, subtle, not-obviously-broken things on my cars.

I'm at 2500 miles and followed the strict break-in rules up to 2000 miles. Even since then I've only gotten up to about 5500 RPM a few brief times. I tend to drive delicately.

Thanks in advance for any tips.

mtony

My 911S with PDK has always had a hesitation between 2600 and 3000 RPM. It's most noticeable in 3rd gear, but can be felt in almost any gear. Dealer basically told me they all do that, and I did drive another PDK which did it also.

meine911

I'm not sure I've experienced the same thing, but from my experience 3rd gear is a long one and very slow to accelerate from low rpm's like 2100. It just doesn't like it there at all. I usually have to downshift to get a better response.

Nicoli35

I think maybe it's something to do with engine warmup or fuel economy when driving delicately. I tend to enjoy revving my engine and haven't noticed anything unusual.

mrstep

Your poor engine is sending you a clear message - don't hesitate to downshift to grab some higher RPMs. Considering that second is safe up to what, around 80 mph at redline?, there isn't a reason in the world* not to when plodding at 32-35mph if you decide you actually want to immediately accelerate.

* I mean, assuming the oil is warmed up and all, but it's not like Porsche doesn't design their engines to run well at higher RPMs. Oh, and assuming you're not in a 15mph school zone or something. And you are past the break-in. Etc., etc.

stealthboy

I really didn't want to come get a lecture on driving style . I appreciate your input, but I'm just concerned that a stumbling in the 2000-3000 rpm range does seem right. It's most noticeable when trying to do 25 mph (yes, like in a school zone for example). I don't really want to be doing 5000 RPM at 25 mph, thankyouverymuch.

Edit - and yes, oil is at temp, and I'm past the break-in period.

MerlinsGarage

Just a thought.........Porsche could be is controlling the throttle position through the mapping of the ECU to the extent of being noticeable, or it could be a matter of cam profile and variable timing lag. These engines may want to live at higher RPMs.

We found that some manufacturers (GM in this case, the late model Holden/GTO) will program the ECU to not allow WOT with pedal position to the floor. The reason we learned was to mitigate drivetrain warranty issues.
Car was a pooch until we reprogrammed ( re-chipped) the ECU and that changed the entire personality of the car.
Porsche may use similar programming.
I would love to have one of their engineers re-map to constant 93 octane with no emmision output restrictions. We are exempt here in PA from such emmision inspection if driving under 5000 miles per year.

stealthboy

Agreed on all points. When I'm in Sport mode and am at higher revs the engine is fantastic. I was just wondering if this was a potential problem, but sounds like I should stop being such a ninny and not worry :-).

carrerapete

I have the manual trans and I'd definitely be in second gear while cruising through a 35-MPH School Zone: It's not a question of being a "ninny": the last thing you want to be doing is LUGGING the engine.

stealthboy

Cruising at 35 in 3rd gear is far from lugging the engine. In fact, the stupid shift indicator light comes on to suggest I shift to 4th! Seriously, if you follow the shift indicator, then you'd be lugging the engine.

Never mind guys - please carry on. If anyone has thoughts on my stumbling at 2100 RPM please PM me. Thanks!

Nicoli35

Hehe, that shift indicator got turned off the first week over here.

extanker

you could get some one with more stick shift seat time to drive/ride and get their opine

MerlinsGarage

OK, seriously, try changing your brand of fuel, maybe it is sensing knock. Also are you in the mountains.......higher altitude?
And yes I would have the dealer run a diagnostic program to see if any non-visual (OBD) issues are occuring.

Bret.

stealthboy

Will do, but I'm not sure how that will exactly help to diagnose a stumbling at 2100 RPM. The whole shifting thing really isn't the issue here - I was just mentioning the MT to differentiate from the existing PDK hesitation thread.

But you're right, having some other opinions while in the car will be only way to really see if this is a concern or not. Thanks. Not having driven another 991, I'm just trying to feel out if this is normal and nothing to worry about, or if I do in fact have an issue that should be looked at. Yes, I'm being paranoid about my new car, but if that helps prevent something major, then I want to feel it out early.

stealthboy

This is a great suggestion; thank you. I'm at low altitude (300 feet - ha), but perhaps the gas itself could be an issue. I always use Sunoco, but it's worth switching it up to rule that out. Appreciate the tip.