Your EGR is unfortunately not mechanically operated. It depends on solenoid operation. If you clean it, from the moment you box it up again if your solenoid is not operating at precisely the correct moment then the coking up process starts almost straight away! Terrible design unfortunately! Get the EGR disabled and your DPF removed. It DOES NOT affect mot. If you have had several EGR cleans then your inlet manifold probably choked up! Remove that and cleaned. Get turbo wastegate valves checked. I spent £430 on EGR and DPF removal, a further £300 on turbo and inlet manifold cleaning!! My Alfa 159 2.4 jtdm had run like a dream for 5 months! I no longer have to drive it like I've nicked it! It drives like a car should! Economically when I want it and very quick when required! It's a lot of money to spend but worth it!