(T) Even FIAT cannot find my SEI fault...

Ive threaded here recntly about my Seicento Sporting (SPI) problem. The car suddenly cuts out when idling for no apparent reason and without warning. Ive now changed the fuel filter, pluds, air filter and the problem still persists. Took it to local garage last week - they could not find the fault.
Took it to main Edinburgh FIAT dealership yesterday, and hey presto, they also cannot find fault (chief foreman had looked at it). Thankfully they didnt charge me!
Has anyone got any idea what this might be? The car seems to be better when i increase the gas to 1000rpm (it idles around 800rpm). But you cannot change idle speed on a Sei. Im now starting to think that its cutting out due to low idle speeds. Can this be resolved? It feels as though there is tiny misfires when sitting in traffic etc, but its difficult to say for sure as the exhuast is right below the seat!
I really dont know what to do next and any help would be much, much appreciated.
thanks in advance
Mike

If the cutting out is not leaving a footprint in the management system memory, then the management system thinks the car is switching off deliberately.

If it thinks it shouldn't be stopping it increases the revs, try turning on your headlamps to full beam and your heated rear window at the same time. The revs should try to drop with the additional load on the alternator, but the management system kicks the revs up.

Check the crank sensor is intact and clean.

Cheers

D

I think this is at leats the 2nd time crank sensor has been sugested

yea i was thinking crank sensor. that or the physical timing is out maybe caused by the timing belt jumping a tooth or 2...

I wouldn't rule out a poor electrical connection, or the Idle steep motor.

Check all the electrical connections, including the Injector...

mine was doing that, i pluged the HT leads in properly and waved goodbye to the engine cutting out. it may be worth trying it, though i dodn't check the crank sensor. Its a start anyway

Hiya mate I think if you try changing the HT leads and buy a can of carb cleaner and spray it into the air filter box with the air filter removed. It really works! Try getting it timed up properly too. Plus if you get a mates ECU and try it with that installed and if that doesnt cure it then feck knows lol! Cya m8, Benji

When it is idling is it smooth and constant? I experienced exactlty the same symptoms with a volvo 440 and it turned out to be a faulty idle stepper motor. I took the stepper out of the equation, blanked off most of the air inlet pipe with tape and it idled better than it ever had.Not sure how relevent this is but i'm sure these engine management systems arn't radically different.

cheers for all the respones, will have another deek at the car this weekend and try to solve the problem.
one thing i will say, after replacing the Fuel filter 2 weeks ago, the car has only stalled ONCE now. It used to happen almost daily (the car gets used daily and frequent). Could this suggest it was a fuel issue rather than electrics?
thanks again