Hi.
My Marea 1,6 ELX is running unstable at Idle speed.
The ingnition system, the ECU and the Idle speed stepper motor has been tested.
Does anyone have an idea?

My 1.6 started idling all over the place, even down to 500rpm. It often satlled as I slowed at roundabouts. It was simply the alternator which was under and overcharging. Not cheap tho'. Maybe you've checked that already but that's what my problem was.

Have a look at the idle control valve. Take it off and give it a clean with Brake cleaner or similar.

Andy.

Thanks guys.
I had a Fiat workshop take a look at it.
They cleaned the Idle control valve, and i worked ,for a couple of days .
Now the problem is back.
It runs at around 850 rpm and then drops below 500 for half a second or so and returns to 850.
This happens with both cold and warm engine.
The car is driving me nuts. (gearbox, ABS unit, air con pump, ignition coil and clutch cable has been replaced within the last year):bang:

i'd try replacing the idle speed control valve with one from a scrapyard car (£10)

Had the same problem! You should probably change the idle actuator! Does it drop below 800rpm with AC on only or regardless of the AC?

The Idle control actuator has been tested OK on a Fiat workshop...
It drops below 800 RPM regardless of the AC.
And now another problem apears, during acceleration with full throttle, the engine also looses power in half a second or so.
It started periodically, but now happens every time i drive.
Sometimes it happens ones or twice in every gear shift.
Any advice is more than welcome...