Hesitation during quick acceleration

[saj911]

I have a 2002 911-996 (3.6L). I have had the car for about a year. I noticed when I try to accelerate quickly from stand still there is a slight hesitation before the car accelerates. If I accelerate slowly there are no such issues. I also noticed when in 2nd gear and around 1500 rpm if I try to accelerate, the car sometimes shudders before accelerating. My mechanic thinks this it may be the MAF but he is not sure. The problem hasn’t been fully investigated by my Porsche mechanic yet. None the less I decided to replace the MAF with a nother genuine Porsche MAF, but that hasn’t resolved the problem. I did some research and from what I can see the problem may be related to MAF (which has been replaced), the Oxygen sensors, VarioCam Selenoid, VarioCam Chain Guide or perhaps even the Ignition coil. The car runs fine otherwise. There are no issues with starting the car or with the Idle. Has anybody else experienced a similar problem and may know what the fix is ?

[shahram]

I I agree with your mechanic, had a similar problem and it was the MAF. But I think also the O2 Sensor can cuase similar problems. I would change both. on 996 it is possible just to change the sensor and not the whole Bosch housing like it is with 993 and you can get the O2 sensor cheaper from Ebay....

[saj911]

Thanks for you feedback. I just spoke to my mechanic. He doesn't think I should replace the Oxygen sensors without performing proper diagnosis first. He says the proper way to diagnose the problem is to put the car on a Dyno and then check for the fault codes to debug the problem. I have the car booked in for next week. Hopefully they will find the fault and correct it. I will update the thread once the problem is fixed.

[ischmitz]

On these cars proper diagnostic is the only way not to waste tons of money. As a minimum you need a PST-2 (Porsche specific scanner) to be able to check if there are any fault codes or unusual readings from the DME. This will tell you if any of the O2 sensors is bad or something else.

Cheers,
Ingo