Porsche Repair: 911 engine stutter around 3000 RPM, timing advance, fuel delivery

Question
Hi, I have a 1971 911E that has an engine stutter around 3000 to 4000 RPM. The motor runs strong and will pull smooth to about 3000 then stutter a tiny bit up to 4000 then run smooth again. If I really put my foot into it I won't notice the stutter at all....may still be there but I just don't notice it.
I don't even know where to start looking. The wires and plugs are pretty new. The cap, rotor, and points are also pretty new. I hate to think it may be a problem with my MFI but I guess that's a possibliity.
Any ideas?
thanks T  

Answer
Hi Tony,

It is a bit of a mystery, but I'd start with fuel delivery as the likely culprit.  At that RPM the cam and timing advance mechanisms are moving much more agressively to move more air and fuel.  If the fuel is not available as expected you could get that stutter.  As for why it suddenly stops after 4000, I'm still thinking.

I'd renew the fuel filter and verify the fuel pressure is correct as well.  That's all I can think of without getting into the fuel injection itself.

Thanks.

Dave