Ford Focus Egr Problems

[firetrappp]

hi i am new to this i don't really know where to start lol

before i have bought the car there was a problem with the car , and car was going to the limp mode and diagnostic couldnt really identify anything , after taking to the ford diagnostic glow plugs has been replaced cost of £500 ( with towing paying local garage etc )

then i have bought the car, engine system fault light was keep coming on , but when i start the car light was going off !! , took it to the local garage , it was egr valve , before i replaced the egr valve i put petrol in it by mistake, then engine drained but fault still there !!!

anyway mechanic cleaned the egr valve with spray that didnt help at all , then last week i have bought second hand egr valve and replaced with these engines egr is part of manifold so couldnt buy it seperatly

i was on holiday mechanic said car driving fine , i have picked the car up this morning driving back home engine system light come back on again

i m not mechanical minded so i dont really know what could it be the fault

gonna take it back there again for diagnostic , but i m thinking shall i take it to the ford and get diagnostic done there

it seems like everytime i fix something , there is another thing coming up

any ideas

by the way car is 2006 ford focus titanium 1.8 tdci

many thanks