Nissan 300ZX efi fault

[Ross Forgione]

Hi all,

I work with a high flying sales person type dude, who is in his 30's and
is suffering from the old mid life crisis problem. Soultion to problem,
purchase a sporty type car. 

The car is a Nissan 300ZX model listed below. Anyway long story short,
he bought second hand from a local car dealer after lots of warning
from myself. Has spent lots of $$'s fixing the usual faults with cars,
(hoses, leaking fuel seals etc ...) but there is one fault that even
the local Nissan (real 100% factory appointed) cannot resolve. I have
listed it below in the hope that somebody out there may be able to
light a small candle showing the direction we should take in resolving
the fault.

Have pity on the guy, It real hard to look cool when the cars on tow
as the pretty ladies go by.

Any help at all will be greatly appreciated.

The problem as follows:

Make: 	Nissan 300ZX Turbo 1986 - Fuel Injected

About 80% of the time the engine has a problem of surging then dying when
at 1700-1900 RPM it refuses to cruise at this RPM level. The engine still
accelerates and decelerates smoothly but will not run evenly whilst trying
to keep at a constant speed.

The problem can be fixed 100% successfully after driving a few KMs by 
putting the car into neutral and switching the ignition off for 2 or more
seconds the restarting the engine.

If I park the car and leave it for an hour or so the majority of the
time I will need to start the engine drive for a few KMs the switch the
engine off and on to get it to run smoothly again.

If I start the engine then stop it immediately then start it again when 
I first get into the car it still will not cruise at 17-1900 RPM most of
the time.

Hot or Cold weather makes no discernable differance to the behavior of
the car.

It is a bit of nuisance having to switch the engine off every time I
drive it.  

I have taken the car to a Nissan Service Centre but they are not sure what
the problem is. They think it may be one of the computers being faulty
but they are not sure which. I dont think much of having to pay $1500 to
have both computers replaced when they are not certain which one it is
or even if it is actually a computer fault.

If you can find anyone that has had similar gremlims let me know.

Thanks,

Ross.