uneven idle and whining noise

Hey,

could anyone here help, i have a -06 Ford Galaxy 2.0 (petrol) and it has a weird problem.
Idling is uneven (uneven running is not shown on rpm gauge) and the car makes a strange whistling sound.
Uneven idling is also reflected in the flashing of the lights and also the unevenness "travels out of the exhaust pipe".

In addition to this, there is a slight delay in the car in the gas, eg when idling, when the gas tramples quickly,
the accelerator pedal already returns to its normal position when the revs starts just rising.

Otherwise, the car works well and is normal to drive and has no significant laziness / lack of power.
The car does not give any fault codes.

The car has been replaced (R) / checked for faults
EGR-valve (R)
Belt tensioner (R)
Guide pulley  (R)
Alternator Freewheel Clutch  (R)
Alternator Regulator  (R)
Waterpump (R)
Throttle body (R)
Spark plugs (R)
Air leaks not found
Intake manifold gaskets (R), also checked intake manifold flaps and crankcase oil breather valve working
Intake air Control Valve is working properly also.

Previous owner have repaired leaking fuel line before injectors with an almost twice as thick hosewith size. could this affect at all?

thanks