Hi there,

 

I have recently got the DPF removed from my q7 and after that i have noticed alot of black smoke and reduced in MPG and Performance. Can anyone tell me why and what is it? 

Have you had the car remapped too? This is normally recommended to match the fuelling with the new improved flow rate through the exhaust. If this is not quite right it could cause the smoking issue you decribe....

The car was remapped before the dpf removed, the person we gave the car to had got it on the diagnostic and has fornd several different fault codes. Not sure what to do.

Could it be a fault lambda sensor? The person who i got the dpf removed had put it on diagnostic said its showing some faults including S104 oxygen lambda sensor, S119 oxygen lambda sensor b1 s1 signal too high,

If it's showing those fault codes relating to the lambda sensors then yes that's a good place to start. There are usually two lambda sensors, one before and one after the cat in the system.

No offense, but any tuner worth their salt would have rectified the problems before commencing work on removing the DPF. 

how did you get on? im looking at getting my Q7 remapped and DPF removed at the same time? 

if the car was mapped prior to the dpf delete then it will need a map tweak now, when the map is tweaked you can also ask them to turn off or extend the parameters of the lambda sensors. hope this helps.