Hi everyone... I have a '14 981 Cayman S PDK. When accelerating in any gear from 2K RPM to around 6K RPM the acceleration is not linear and smooth - it surges and is slightly what I can best describe as lumpy. It's not an intense phenomenon, but enough to be noticed and annoying. Do any of you with this car experience anything similar? Any ideas what it might be Id it is not normal? Thoughts? Thanks much!!!

 

Have not noticed that on my Boxster S 2013.....

 

Contact your dealer, the car is under warranty and that is not normal.

 

Thanks folks ... Didn't think it was right. I will share findings when I learn them.

 

Ok so was able to take the car in yesterday - they drove with me in the car and looked for codes - conclusion is fuel issues due to winter gas blend transition. I'm told the DME has to adjust with changing input from knock sensors etc. Said next tank or two should show marked improvement.

I've heard of this kind of thing before - fuel blend effects - but have never experienced any ill effects firsthand. I will give them the benefit of the doubt and follow through.

 

Well, that's BS. The DME adapts constantly and immediately to the knock sensor signals. If it didn't the engine would detonate itself to pieces way before you went through a tank of fuel.

What is probably more likely is the engine just doesn't like the fuel. Could be an off batch of fuel, perhaps you filled up from a gas station storage tank that had some summer and winter gas mixed, or you got some stale fuel.

As I like to advise buy a top tier fuel, preferably form a name brand station and buy from a busy station to get the freshest gasoline.

My advice is to avoid discount gasoline brands. I know they are a few cents per gallon cheaper and to save some money is a powerful attraction but my (unscientific) experience is when running discount gasoline in my Boxster a marginal converter was more frequently triggering a CEL compared to when I switched over to a top tier/name brand (Shell) gasoline.

In case the engine doesn't like the fuel consider at least trying a different brand of fuel next time. (This is what Porsche advises in the owners manual.)

Oh, one thing you might want to try is to perform an e-Gas recalibration operation.

How to do this should be covered in the owners manual.

For the earlier models it goes like this: During this process do not touch the gas pedal. Turn the key to the on position. Leave the key on for 60+ seconds. The time can be over 60 seconds but shouldn't be under 60 seconds. After 60 seconds turn the key off. Leave the key off for at least 10 seconds. Done.

The next time you start the engine the e-Gas electronics will be properly calibrated.

 

Interesting thread, i just bought a 2013 Boxster S just under a week ago and I'm experiencing a little what I would term more of a slight bit of hesitation in the higher revs but maybe very similar to what you're experiencing - don't notice it up to mid rev range but as it climbs past say 4k or so, maybe 4.5k it is not smooth and as you say linear- very subtle but there.

I was thinking it maybe that the previous owner didn't rev it up enough and it needs to be driven harder to get it "blown" out a bit. I've filled up again with Shell so I'll be driving it on some twisties coming up in 2 days and I'll report back. I have mentioned this to the dealer so this thread is talking to me too!

Great having this great RL group to bounce this off of. I'll also try the 60 second thing.

Thanks OP - great thread!

Tim
The Villages, FL (moved from Atlanta a year ago)

 

It is possible the engine needs some real use. This is not to say you need to drive the car like you stole it, only that a good run of 40+ miles at (legal) highway/freeway speeds could help.

More than once I've driven one of my cars this distance or further and the engine really improves.

The car is new to you and you may be dealing with a car that wasn't used much, driven short distances, maybe fed a sub-par gasoline, could even have stale gasoline in the tank. Often cars for sale sit a long time and the gas can go stale. The seller might also fill the tank with regular gasoline instead of premium gasoline too. Often the seller falls out of love with the car and decides to no longer fuel it with the right grade of gasoline. In some cases he might have fallen back to using a sub-par gasoline tanks before you bought the car.

My last used car purchase, in June 2009, I bought a low miles (10K) 2003 996 Turbo. One of the first things I did was run a bottle of Techron through the engine as per directions on the bottle to clean the fuel system, the injectors, etc. The previous owner only put 10K miles on the car in 6 years, that's 1667 miles per year average, and I didn't have any reason to believe the owner skimped on gasoline, I just suspected the engine could stand a bit of (internal) cleaning.

If you decide to take the car out on an extended drive I might mention that if the engine starts to exhibit any other odd or untoward behavior, if the CEL comes on, you need to get the car to a shop ASAP. If the engine sounds or runs sick you probably should shut off the engine ASAP and avoid running it any. While I don't think what you are experiencing with your car and engine is anything serious, I offer the above just in case.

With that out of the way....

Gasoline is important.

So is oil.

The variable valve timing hardware is controlled by oil (under pressure) and this oil wants to be the right stuff. Variable valve timing kicks in at just over 5K RPM's in the older engines but could kick in earlier in the newer engines. If the oil is past its change by date or the wrong type or of the wrong multi-viscosity grade this could affect the variable cam timing hardware and result in a stumble or hesitation if the variable valve timing hardware didn't react quick enough.

 

I have same issue here.

between 4K~5K rpm.

I have aftermarket exhaust(m&m), not sure if that causes this.

pretty annoying...

maybe remapping ecu will fix this problem?

 

Mines a CPO car, dealer was a premier dealer, Hennessy, and they have their own pump with Exxon HT, they also did an oil change and brake flush. I need to put it thru some paces and see if that helps. I just drove it 400 miles home and hit 100 once briefly - car is fast! I've noticed a sound that may be the beginning of the water pump going bad.....we'll see- one great reason to buy CPO !

I'll be back to report after Sunday's romp...

 

One word - AWESOME....I know tired word but it surely serves! No hesitation - no lumpy accelerations anywhere- it just needed some high rev driving and it didn't disappoint! Absolutely amazing car - nothing like stretching one of these guys out - I mean! Unreal, definitely the fastest car I've ever owned after 3 911s and an NSX. Really, really happy! Hope the OP gets his straightened out - but you do have to blow em out.

 

As I've mentioned before a number (almost all) of my cars their engines have benefitted from a longish drive.

While my work commute is (one way) 30 miles and most of these miles are freeway miles except for rare days (early Sunday mornings) the drive is congested enough that I can't maintain anywhere near the 65mph limit for any length of time.

But a drive of even just a steady 65mph to say 75mph speed for a distance of around 40 miles or so has in my experience the engine running much much better.

Now the engine was not exhibiting any real signs of trouble or distress before hand it is just the engine is much smoother, more readily accepting the throttle, more responsive after the extended drive.

(In one case where the Boxster failed a CA smog check after consulting with the two senior techs who maintain the car I took the car out on an extended drive and this time because of time pressure I resorted to a few hard acceleration runs up through the gears on a deserted country road. The car still got a good drive but I tossed in the hard acceleration runs for good measure as I didn't want the car to fail the second time. Afterwards back at the smog check station the engine passed with flying colors. Now I will point out that the engine and converters were quite warm from me having driven the car around an hour or so before the first test to ensure everything was warmed up as I know how critical this is to a good smog test result. But the extended drive did something for the engine and the converters. The techs in fact told me that often when they get a used car in to smog before the car goes on the lot either the SM or one of the senior techs -- with the permission of the GM/SM -- drive the car home and back the next day so the engine passes a smog test with no problems.)

I am not advising anyone with a sick engine to take an extended drive. If the engine is misfiring, making noises, in any way acting up there's probably something wrong that a drive will not help and could make worse.

But an otherwise healthy engine appears to appreciate and benefit from an extended drive. I mean if one won't drive the car any for his own benefit at least think of the poor engine and give it a nice stretch of the legs once in a while.

 

I agree with Macster...mine had just been on a 400 mile trip and I took it out the other day and just put it thru some paces and it performed flawlessly. I think it just needed to get the stale gas out and be run with purpose. These cars really need spirited driving - that's really what they're made for! I think many who buy them would freak out if they ever really put their foot on the loud pedal and let it go. Some buy these cars as status symbols or because everyone that wants a "real" sports car gets a Porsche - right - then after a year they just decide to get back into a more luxurious sport sedan. Not everyone that buys these cars is a serious "car guy".

 

TheDatanator, you said you would report back on your problem, but I don't see a post with the resolution.

I recently bought a brand new Cayman S, possibly the last 6 cylinder car for the US, and have had the same problem since day one. There are hesitations and surges when trying to accelerate at moderate levels. There is no check-engine-light. The dealer is trying to tell me they all do do that. For daily driving, it really spoils the driving experience.

I have tried Sunoco and Mobil 93 octane gas and even Sunoco's pure gas (no ethanol) 91 octane. No difference. I have done a DE at Watkins Glen, so the car has certainly seen some "spirited" driving. No improvement. I've searched my manual for an e-Gas calibration that Macster mentioned and can't find anything.

 

For the last 2-3 months I have been experiencing this lumpy acceleration in my 2013 3.4 Boxster especially in the 2500 to 3000 RPM range when the car is in a higher gear and under the load, like 6 or 7 (PDK). No doubt the fact that I have been making short trips primarily during the 2020 year of COVID-19.
I am going to take the advice of putting Techron in the tank and going on back roads where I can really do some acceleration and warm the engine up and hopefully burn out the lumpiness like previous owners seem to have done according to this thread.
I will report my results!