New to me 2008 Cayenne S has a slight hesitation driving hwy speeds. Seems to only occur for example just after the lowest spot on the road between two rolling hills as the vehicle goes from 'coasting' or less power to when the engine starts to pull more to climb a slight incline. Just feel a slight hesitation of perhaps 1/4 s (hard to say) after which the vehicle just continues on. Never happens upon deceleration or acceleration, just that very slow change as described.

I have a 996turbo and it is similar to when driving on the highway and the turbo kicks in very slightly there is just a subtle jump in the drive train.

I could say that this hesitation is so subtle that without a very smooth highway and anticipating for it to happen many drivers may not even notice.

Just curious, I searched a bit but did not find anything.

The driveshaft was replaced only a few months ago, and I just drove it >700mi with no apparent degradation of this issue. Maybe it is normal?

Thanks!

 

Just wondering if anyone can confirm the question I previously posted??

Is this hesitation / stuttering in the transmission as described normal or not normal?

I have since driving the vehicle on several long trips, just recently over 1000 miles and no change in the conditions.

Searching has not found a single instance of this problem which seems odd unless it is normal.

The only conditions remotely close seem to be transfer case issues, but the symptoms are generally described much different.

Anyone please?

 

Could be a few things.. Fuel pump, throttle position sensor, etc...

 

Could be early signs of Oxygen Sensor failure if its a high mileage car. I had hesitation which got worse over time , with no fault codes. Eventually turned out to be primary oxygen sensors.
If you have a decent diagnostic machine you should check the response times on your oxygen sensors. If they or one of them is failing it may produce this symptom. Sluggish oxygen sensors can produce symptoms without producing fault codes.

 

Thanks for the input. I do have a diagnostic device and it shows many parameters. Some show similar results for bank 1 and 2, these are different. Not sure what I am looking for exactly. These were logged during a cold warm up of the vehicle.

Dyn measurement o2 sensor before cc bank 1 = 130.83 rk (degrees)
2 = 0

O2 sensor adapt bank 1 = .95
2 = .49%

Dyn value of o2 sensor upstream of cat conv B1 =.16
= --


Also, Pedal encoder pot 1 = .7 v
2 = .4v

 

The value to look for is the rich to lean switch time on the o2 sensors before the cc , these should be pretty much the same for banks 1 and 2.
This is normally measured in milliseconds.
Also you should take measurements with the engine at normal operating temperature (to ensure closed loop operation).
Initial evaluation would be to check that banks 1 and 2 are the same.
You can normally find this under mode 6 on a normal OBD2 type reader.