Winterreise

I would appreciate any feedback on what I am noticing with my 05 Cayenne base engine performance. It has 99k miles. There are times when the performance (acceleration) is quite brisk and quite satisfying. Because of the Porsche architecture for the intake and tuned exhaust systems with this VW block, the sound of the engine as it passes 4k-5k rpm is quintessentially PORSCHE in timbre. Wonderful.
However, at other times, usually when the engine coolant and oil reach their normal temperature, the responsiveness seems at times diminished, even sluggish. When starting out on a drive in the winter for example, the car is very quick. On a summer warm day, less so. Is this block expansion, slightly decreasing the compression PSI? Does different octane or even different brands of fuel make a difference?

Thanks for any help

endless_corners

Wondering about MAF and air filter. Try cleaning your MAF and obviously make sure air filters are good.

LaicepsYdobon

Fuel can and does play a part in the difference in performance. Even when you fill up at your favorite gas station that you always fill up at you will notice when you get get a subpar tank. Just recently I've even switch gas brands because the brand I was using made my engine ping. Switching to the different brand stopped the pinging and according to my butt-dyno the car feels more powerful/responsive.

ryan09

+1 on the MAF sensor. I have an '06 3.2 and experiencing the exact same problems you're describing. I replaced the air flow sensor today like two hours ago, what a coincidence you posted this thread today! Anyways, it seems a lot more responsive after replacing the sensor.

I will keep you up to date since I didn't have a lot of driving time after changing it.

Slow Guy

Is there only 1 MAF sensor on the V6's?
Just curious.

ryan09

Yep only one of them on the V6.

virkdoc

Any way to check the MAF? What would the symptoms be of a faulty MAF? Can durametric diagnose it?

endless_corners

A fault will only show up when it's really bad. I suggest buying some MAF cleaner and spraying that thing clean. That's the cheap way to begin. Because the MAF sensor is basically a wire stretched across a plastic tube. Intake air is rushing over it and it can become coated with a thin film of funk. If it thinks a lower volume of air is entering the engine it will retard fueling/timing/etc accordingly. Just make sure to specifically buy MAF cleaner so that it won't damage the sensor.

Winterreise

Thanks for the tips, all. I am not sure what MAF means? If it is a sensor, where is it located and can I clean / replace it easily myself?
Thanks,
Bob

endless_corners

Mass airflow sensor. It on the intake tube after the air box. It's measuring air volume. Shouldn't be too hard to find or get at. I have the v8 so there are two on mine. Not sure what the plumbing looks like on the v6. It's slightly fatter and shorter than a can of soup.

ryan09

It's a very easy installation, you can do it yourself. It literally took me less than 10 minutes to replace it. Shoot me a pm if you need help.

I've been driving it for two days now and it made a huge difference. It's a lot smoother when reaching high rpm and doesn't feel sluggish at all when the engine reaches normal temperature. I would definitely try cleaning it first like others have said.

Winterreise

Thank You! I thought this was the MAF sensor. Could not be any easier to access. I will buy some MAF sensor cleaning spray and try cleaning it tomorrow. I will report on the performance change ASAP
Bob

Hud99

Ryan, how many miles before you changed it? Did the old one show signs of accumulated dirt?

ryan09

I have 67000 miles on the dash. The old one was pretty dirty and I noticed it was a bit loose on the right side, I secured it with a little tie zip between the clip-on.

Winterreise

It has been three days since I cleaned the MAF sensor. The air filter was changed at 83k - I'm at 99k so its fresh enough? I am noticing a stronger pull as is my son, who occasionally drives it. I think the performance has improved. Thanks to all for the suggestions.
Bob