Air Flow Meter + car problems

[Jeremy Edmondson]

avos at cochlear.com.au wrote:

>      Recently my car has been performing badly at low to medium revs as
>      boost comes on. It seems to fiddle around with settings when you
>      initally put your foot down until it decides what it is going to do (a
>      few seconds sometimes) and then it runs great. It is annoying under
>      hard acceleration, as it will hesitate and then hit you with an
>      almighty boot in the back. I am sure that this is not good for my
>      engine, and have lowered my boost level to ensure that I will not
>      damage anything. I have replaced the fuel filter, oil and oil-filter,
>      spark plugs, and cleaned the air-filter in the hope that it may be
>      some blocked filter, or bad spark, but all this with no success. I am
>      starting to wonder whether a sensor is working incorrectly on my efi.
>      I have several other ideas before I narrow it down to the efi - fuel
>      pump (not supplying enough pressure), fuel pressure regulator (Does
>      anyone know how to check the fuel pressure is constant under engine
>      load on a 4WD car for which I do not have access to a 4WD dyno),
>      fluctuating boost (though this is not apparent from my boost guage),
>      blocked injectors (though I have run petrol additive injection cleaner
>      with no effect on the problem). If all this fails I will no know where
>      to start - Does anyone have any ideas on what could cause such a
>      problem. The weird thing for me is that it seems to run fine once it
>      has started to sought it itself out and reached high revs, which seems
>      to me to rule out the chances of it being a fuel delevery problem?
> 
>      Any advice will be appreciated, I am starting to my pull my hair out.
>      Note that my car has had no modifications done recently, and ran fine
>      for a year with the modifications that it has, so I doubt that it has
>      anything to do with any modifications that I have done.
> 
>      Adrian

Try the coolant temp sensor, I have had one of these go, it made the
engine run rich though.  The EFI thought the enigne was always cold. 
May not be your problem but is really easy to check.  I do not know what
the resistance should be, the value is usually published in the service
manual.