996 Flat spot at 5000 rpm

[brisel]

Just been from Lincolnshire to a work related show near Abingdon and back with my boss in his 996. When he floored the accelerator for an overtake the car felt underpowered and coughed at about 5000 rpm, yet when the pedal was 3/4 down full power was available.

The car is an MY1999 996 and is always service by a Porsche dealer

Any ideas? Air flow sensor? ECU software?

TIA

[Ir Baboon]

Another one to add to the list is coil packs - might be worth getting the OPC/Specialist to plug in the diagnostic box

Good luck

[fastfreddy]

I had something similar a while back. Turned out to be an engine sensor, but can't remember which one right now. The service manager of my OPC at the time couldn't even feel the hesitation when he drove it, which was worrying...

[Mousem40]

Quite likely to be the MAF. You can try cleaning it, that generally does the trick, do a search (here for example http://www.pistonheads.com/gassing/topic.asp?f=48&...

[ricardo60]

MAF _ Ive had two. Ive also paid OPC to order & fit. A mate of mine ordered off Europarts and was the work of a moment to fit.

[batman69]

MAF almost definitely. As said buy from Europarts and fit yourself.

[PolarExpress]

If it's repeatable at around 5k rpm, it could also be the Variocam solenoid actuator that is a bit sticky and not always actuating as the 1st stage Vario is supposed to kick in. The Diagnostic tool can test this solenoid specifically, but it requires the engine running at the same time when you can also physically hear it actuating if you open the engine lid. (a bit tricky deciphering the noise from the din of the engine as it goes past 5k rpm, but it is discernible).

Edited by PolarExpress on Friday 14th September 09:30

[fastfreddy]

I checked and mine was the MAF sensor too. Flat spot around 4500 rpm. Sounds about right.

[brisel]

Cheers, guys!