help ford focus mk2 1.6tdci feel sluggish at times

[soulZ]

Hello I have a problem with my ford focus 1.6 tdci.  At times it feels I am loosing power and at times the car fly's. Their is a light on my dash saying engine system fault but had the car checked at few garages on the machines and all coming back with no faults. My car makes a strange electronic we I switch it of sounds like it is coming from the turbo and also their is a little rod near the turbo which moves up and down at the same time . But when the noise stops then the rod moves down and stops. It is strange because it happens everytime I switch of the car. I have also serviced my car but no cure. Please if any help or any 1 had similar problem. Cheers

[1.6 tdci zetec s]

I've got 1.6tdci fiesta, mine makes a noise when i switch engine off, i thought it was the power steering shutting down, sounds like a servo. Get forscan on your laptop plugged into your obd port see if you can find the dtc that's showing your light on the dash. There's some good lads on here that can help you find the best way forward, have you got a code reader of your own?  They're cheap on eBay or amazon 

[soulZ]

I went to rj performance in Birmingham and he plugged in his computer with no faults showing and also I went to a few garages and all said it's coming back with no faults. Am not sure what is playing. Am hoping it's not the turbo. But am not sure if it's the turbo actuator. Does your car feel any sluggish at times. Cheers for reply pal.