Abit of a newbie at this so bare with me.

I have a Focus estate 1998 1.8TDDI done 135K miles. No smoke and runs great however when pulling in 3rd and 4th more noticeably it lacks power from the turbo just before 3000rpm. I have read some of the other posts but I couls not see the same problem I have. Car seems to be fine in 1st and 2nd. I have no idea. I have had the intercooler off made sure all claps are tight. There was some oil spray from one of the hoses from the intercooler but i have had the pipe off and looks of and tightened it up. Does anyone have any ideas it would be much appreciated.

Thanks

Stevie