I have a 1.9 tdi 130 2004. It has had a 170 bhp remap. I've not had it long but I have noticed a decrease in power and throttle response, when I pull away there's a small cloud of smoke behind me. It now definitely doesn't feel like 170 bhp. 

I am led to believe it is a blocked or blog EGR valve, and having researched a little it does appear so, there is also a small amount of oil deposits around the egr. I'm probably going to buy an EGR delete.

Any help would be great please

Unfortunately you'll not know until you take it off whether it's blocked or not, is there many miles on the car, the egr valve will be the most likely, but before deleting the egr clean it and put it back on to make sure that's going to get your power and accelerator response back again, 

Agree with Jonathan, well worth having a go at cleaning it first!

Going to have a look this weekend, tbh I was going to delete it anyway and will probably order one from darkside this week. 

How did you get on over the weekend Stephen?