deano51

Hi all,
I have noticed recently a "blip" or hiccup--a sort of really quick misfire, although I hesitate to call it a misfire--as I cruise along the freeway in 6th gear at around 3k RPM. It happens randomly and there seems to be no drivability problems with the car, a 2003 911 with about 12k miles on it. I bought the car 3 weeks ago with about 10,800 miles on it, and it is my first Porsche. I'm wondering if this is just a characteristic of the way these engine management systems work or if it indicates something a bit more sinister. Any thoughts or ideas?
Thanks!
Deano

kilrgt

Is it around 3000 to 3200 RPM??...Could be variocam..need more info

NNH

If it's around the 3k mark, I'm sure klirgt is right to say it's the Variocam engagement.

BruceP

If it was a misfire, you'd get a CEL.

deano51

Thanks guys. Your suggestion that it could be the variocam gave me something to search on and, from several other posts, it seems this is common and normal.
Deano

NOBY

Just curious, what is a variocam?

Ray S

Variocam - Variable valve timing ('99-'01 996's)
Variocam plus - Variable valve timing and lift ('02-'04 996's)

http://wheeltalk.fancal.net/?p=366

rleeq

A good test would be to bring the RPMs to +4500 and see if it happens at that speed. That’s well after the variocam engagement point.

jasper

Yeah - at about 3200 rpm, the hydraulics kick in and the valves lift higher. Definite bump at that point. Entirely normal, but I still try to avoid cruising at that speed to avoid constantly engaging the mechanism.

One guy on the board here runs 15-50 weight oil an dhe says it dampens the effect. Not recomended though.