Gastro

This is a long shot - but thought I'd ask the mechanic audience on this one ....
911 Carrera 3.2
Problem --> car stutters at 2000rpm (on light throttle setting - usually in 4th/5th gear)
Feels like its missing or the mixture is lean
Had it in Autofarm twice now - they can reproduce the problem but arent sure what the problem is.
So far the following have been replaced :-
- HT leads
- Rotor arm
- Distributer cap
- Cam sensors
- Throttle micro smitch

now - the car runs 'better' - ie smoother, more power etc but absolutely NO impact on this stutter @ 2000rpm

Any ideas - anybody !?
My thoughts were

1) ??faulty ECU
2) ?Fuel pump
3) ?Injectors

Please help --- its driving me mad

Gastro

Sparky1066

My Dads 911 Carrera SSE was doing something similar to this about 3-4 years ago and he had to have the engine out to get it sorted.
It cost about £2900! I'll ask him in the morning what it was, and describe your cars symtoms to him. He'll probably know what the problem is.

RB5#295

I know of one that used to just cut out for a few seconds at a time, that was the ECU.

Fuel pump relay may be worth changing.

Otherwise timing sensors on the flywheel?

Fen

Gastro

Ok - thanks guys - I look forward to hearing any other thoughts..
And I'll keep you posted !

Gastro

Mufasa

I would blame the airflow sensor.
Have Autofarm tried a known good one?

Gastro

Yep - Autofarm have replaced that - and no difference
I should say that it stutters only on the a constant light throttle ie cruising @2000rpm --> once you accelerate beyond this it the stutter disappears....

Gastro

Mufasa

Well if they swapped it for a definitely known good one then it isn't that then.

Have to say it still sounds like a dodgey AFM to me.

It's an old Bosch flap type meter and they spend most of their life wearing out the same few tracks (that correspond to light load running) on the circuit board.

Gastro

Thanks - I may ask them to replace it anyway (they tried one - and I'm not sure whether it was a new one or one they had lying around !)..
Believe me if its that - I'll be over the moon.

Cheers,

Gastro

Gastro

Sparky - Any more information from you father ?

Gastro

Gastro

Right - they have tried a new ECU - no better, brand new air flow sensor - no better....
They are now going to try a new throttle body switch and a new coil (the last one had signs that it had been arking...)

Any more ideas ?

Gastro