Strange Acceleration Behaviour

[Guest]

Hi,

I have a Cayenne S 05 which has today started showing some strange acceleration behaviour. I can replicate the problem every time by cruising at 30mph (where D4 is the gear selected) and gently accelerating up to 35 ish. The result is a very noticeable shudder under foot.

It you kick down or drive hard, the problem isn't noticable. The car seems perfectly OK otherwise. Driving in manual mode with the same pattern above gives the same results.

Nothing has happened to the car except topped up with fuel yesterday (Shell VPower - usual brand, usual garage). Also, when I started the car this morning, I hit the accelerator whilst I had my foot on the brake to start. There was a slight smell of excess fuel being burnt from the exhaust, but that shouldn't have caused issues.

I've removed the fuel cap in case of an air block in the fuel line.

The car is covered by warranty until the end of the month.

Any ideas??

Cheers
Pete.

 

[Gander101]

Pete, Hi,

Not something that has been brought up before. As the the car is still under warranty I'd be inclinded to get it back to your OPC for them to have a look at.

Paul.

 

[pwebb]

Peter
May be a similar problem to my last KNS. This had a hesitation in acceleration and resulted in new plugs (under warranty). OPC took a couple of attempts to trace the problem though as it didn't show up on the diagnostic (or that was what I was told).

 

[MarkK]

Get it back to the dealer ASAP!![]

 

[Alscoob]

Had similar with un even idle at some times, turned out to be corroded coil packs.. changed under warranty though. As long as its not a judder between changes to 3rd & 4th at similar speed as mine ended up with a new gear box to cure that!!

 

[NIL98]

mine has similar traits, im convinced it actually improves with 98 ron fuel. Dealer says its common fault with coil packs breaking down but computer doesnt seem to record the fault. As its a bit expensive chaning all 8 Im putting up with it for now until its a bit more reproduceable.

 

[sportsandclassic]

Hi , as said before coil packs are prone for causing this problem but they have dropped from £33 to £13 a coil pack...! from any OPC.... just fitted 8 the other day to a V8 non turbo.
As for shifting problems between 3rd and 4th gears,a hydraulic valve chest will fix this problem 9/10 times we have done 4 now,costs around £1400 to to the job as opposed to new g/box and remove engine assembly! £7K +/-

Hope this helps.

Mike

www.sportsandclassic.com