I am attempting to fix a problem with my 2009 Fusion 2 1.6 petrol which occasionally stalls when slowing down / stopping. The revs suddenly dip from ~1000RPM to 500RPM, most of the time the engine stutters and recovers just in time, but sometimes it stalls completely.

In my quest to cure this I have cleaned the throttle body and changed the spark plugs, HT leads and air filter. While these did make small incremental improvements, it does still exhibit this behaviour. I have read on some Fiesta forums about the Idle Speed Control Valve being the cause of similar idling issues on Duratec engines. Is this something which exists on the Fusion?

Thanks in advance for any helpful suggestions!

idle control valve possibly, any codes ? engine management light appear at all ? -  have you run obd diagnostics...

On 9/9/2021 at 2:54 PM, plissken said:

I have read on some Fiesta forums about the Idle Speed Control Valve being the cause of similar idling issues on Duratec engines. Is this something which exists on the Fusion?

I very much doubt if a 2009 car has an Idle control valve. Normally these were used with cable operated throttle valves. The fully electronic throttle control on almost all modern cars means the main throttle body can control idle speed, and there is no need for an expensive 2nd valve. See:

https://ford.7zap.com/en/car/54/no/20/1556/15485/

Most likely cause is a problem with that throttle body, but you should read the codes first. Cleaning a throttle body will only deal with problems due to dirt or thick oil. Electrical problems in the motor or position sensor, or wiring, or ECU, will not be altered by this. Due to the way all the engine sensors are inter-related, it could be another part entirely.