Help! Bucking 75.

[Stuart <stuart.thomson@domain.elided>]

Hi all,

The 75 3.0l (12V, Jetronic) has started (quite suddenly) to suffer from a fuel delivery problem.

Here's the symptoms;
the car starts easily
seems to run OK
after a while (sometimes immedeately) the car start to run poorly
playing with the accelerator sometimes help, sometimes not.
seems to happen under load initially, but will happen at idle, or with the car not moving
seems to be temperature independant
holding a steady non idle rpm engine can stall

Here's what's been done;
Replaced fuel filter
checked fuel pressure (OK)
checked coolant temp sensor (OK)
checked for ht ignition at dizzy, and plugs (OK)
fuel injectors cleaned mechanically (actually did this the other week b4 the problems)
checked the operation of the dual relay set (OK)
checked voltage at the injectors - seems to drop corresponding to the missing
checked mechanical operation of the AFM (OK)

questions
Is the ECU knackered?
how should I check the electrical operation of the AFM?
what else could this be?
how do I test the O2 sensor?

That's all for now,  thanks in advance for the reponses.  

I'm off to the AROCA track day at Winton tomorrow, in one of the other cars.  The driveway's a bit depressing at the moment, four cars, three Alfas, two not working, but a track day at Winton is always enjoyable.

Cheers
Stuart Thomson

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