hi muckers

i have a massive problem with my veccy,below 2000rpm there is no pull at all then after turbo kicks in it goes like it should do it has just started to do this ,so i have put some injector cleaner in the fuel tank now so waiting for that to work through. the managment light came on today as well but the spanner/car light came on first then that went out which was replaced by the managment light,the only other things i can think of would be to change the air filter and fuel filter,other than that im lost .
has anyone local to me (newport south wales )got a diagnostic checker thingy mabob that i could use or is it something more serious,please
any help would be great and very much appreciated

cheers
mark