Mondeo Zetec S 130 TDCI-2002

Ive recently changed where I purchase my diesel from... Used Shell diesel as a rule for the last 2 yrs and changed to Tesco diesel (for the wifes points) for the last 3 full tank top-ups... Noticed a difference in mpg but I expected that... What I never expected was a massive difference in Turbolag, a sort of fuel starvation for a split second especially when cruising and also an increase in black smoke when accelerating(normally a puff then its gone) but not it seems to be continuos when the pedal is depressed in the lower gears when the turbo decides to kick in.... I am very worried at the moment as I travel alot of miles every weekend to and from work and its my weekend chariot...
I have read a few ideas on the forum 32 pages to be precise but thought it easier to post so all the QUALITY MEMBERS can read and I will take all advice as good advice and act on it....
Dont want to be hit by massive garage costs when it could be the fuel change..Hopefully....(me thinks not.. as Im not that lucky)

Anyway thanks for reading this and awaiting your Quality Advice..

PS Im in Middlesbrough for the next 4 days so if you know of anyone who can look/sort it would be gratefully appreciated...

Many thanks WETBUTSAFE

the mondeo can be fuel sensitive,you can check for a split intercooler pipe,which is the large pipe on the bottom of the egr valve,if this is split it would produce black smoke and a hic-up in power, also if the valve has never been cleaned i would also look at doing this all it will cost is some spanner time and a can of cleaner and there are guides on how to do it on the web.