981 PDK hesitation/shunt

[Mario149]

I'm pretty sure I'm not imagining it - I'm convinced that when I'm in a high gear (say 4th or above, may happen lower but it's difficult to tell) at medium revs (say 3k or so) if I'm cruising and suddenly plant my foot (in manual mode or without the car changing gear) there seems to be a hesitation/shunting/bumping for a sec or so before the car accelerates cleanly. At first I thought it was just the little bumps in the road you feel fooling me as I was obsessing - it's that mild, difficult to tell whether it's vertical or longitudinal - but the "bumps" always seem to happen more for the first second or so when accelerating as described.

Anyone else had this problem? Either feels like the engine is hesitating or that the PDK clutch is slipping...or that I'm going nuts.

Car is booked to go for its first service in July, so trying to work out whether to wait until then to get it looked at, or take it in before. Feel quite bad about doing the latter as it's already been in twice for warranty stuff and one of those was me being an idiot :/

[Mario149]

ellesmereFNC said:

We have the same problem on our GTS, its going into the dealer on Monday to look at this and a couple of other bits. Feels a bit like a fuelling issue as I initially thought it was the traction control kicking in.

Thanks for the comments so far. To be honest if if had to put money on it I'd say it was engine rather than transmission related, maybe fuelling as suggested above^^. Like I said, feels like hesitation. I've driven cars where there's drivetrain shunt and the slack is taken up only once I.e. one bump rather than a series of them.

[Mario149]

ellesmereFNC said:

Just dropped the CGTS off at the local OPC, went out with the technician and the initial thoughts are either a failing coil pack or a sticking / failing valve train solenoid...

Guess i'll know later on, also this happens in auto or manual and makes no difference if its in standard, sport or sport +

Good to know, I may try and get mine in then before its service in July.

[Mario149]

Have bitten the bullet and booked mine in for Friday. They'll look at the exhaust tips as well while they're at it as they appear to have the par for the course corrosion on them.

[Mario149]

ellesmereFNC said:

Well that didn't sort it...!

Technician can feel the problem but car has no fault codes, the search will continue.

Oh no! What a pain! The hesitation on my car now seems to be intermittent, could feel it yesterday but not the day before

[Mario149]

ATM said:

I've noticed a small problem with mine. When I'm going slowly in say 3rd and I start to brake gently I feel a shove or shunt as it downshifts to say 2nd. These downshifts used to be smoother than a smooth thing. Now they are noticeable.

Funny you should mention it, but I was also thinking that some of the gear shifts weren't as smooth as they used be.

[Mario149]

ATM said:

Mario149 said:

ATM said:

I've noticed a small problem with mine. When I'm going slowly in say 3rd and I start to brake gently I feel a shove or shunt as it downshifts to say 2nd. These downshifts used to be smoother than a smooth thing. Now they are noticeable.

Funny you should mention it, but I was also thinking that some of the gear shifts weren't as smooth as they used be.

Right

If I bought the car today I would not think anything of it. But I have experienced better 12 months ago. Is there any adjustment for the clutch [as it ages] or is this all automatic / computer controlled.

Have no idea.

[Mario149]

Okay, update on my car. It went into Porsche Guildford today and chatting to the service chap it seems it is a known "feature". According to him it's due to the cam variator switching the cam profile to a high power one as you get on the loud pedal. Apparently they had a Cayman in last year with the owner giving the exact same symptoms. They had it it for 2 weeks, changed ECU etc etc, couldn't find anything wrong and found that other cars they had did the same. Then Porsche in Germany confirmed it was expected behaviour.

They're going to plug it into diagnostics anyway to check, and I also mentioned the PDK not shifting quite as cleanly as I thought it used to, so they'll take a look at that as well.

Given that the hesitation is so minor the explanation makes sense to me, but we'll see if they come up with anything else.

[Mario149]

ellesmereFNC said:

Well our GTS now been at the dealer for 2 weeks, Germany involved but not sure yet whet they think it is...maybe they'll just swap it for a GT3!

Update on mine: dealer checked it over, no faults anywhere. I've driven it quite a bit since and I can still feel it occasionally and it's very very mild. If your issue is genuinely more noticeable (you have to really be looking for it to feel it on mine) it sounds like either your issue is different or that maybe your cam variator isn't "variating" quite as swiftly as mine i.e. not "broken enough" to trigger an error somewhere. As I said before, Guildford told me they went right round the houses for a couple of week with this last year on a Cayman and in the end Germany said "that's expected".

[Mario149]

OP here. I never got to the bottom of it other than the dealer saying cam variator. From memory since it was so mild and a bit intermittent I just lived with it. I sold the car a few months later and swapped into a 997 GTS manual (because children, not due to the issue).

samliv said:

This thread is old, so likely those that contributed to it may not pick this up. I have a 2016 981 Cayman (non S) manual - pretty much last-of-the-line. Have much the same issue as described here; slight engine faltering (mostly at c.1600-200rpm) under light load, worse when cold. Dealer had the car for two months and replaced 6 Spark Plugs, 6 Coil Packs, Valve Lift Solenoid, High Pressure Fuel Pump under warrantee. Fault remains. Just been advised subsequently that 'they all do this' as the Variocam tips from one to the other mode (or similar). I had thought that the Variocam would change at higher rpm (say 3500 rpm); but the main question here to those that had this issue is: did this fault it worsen / develop into something more? Thanks in advance for any repossess here, Sam.