Just a little follow on to this thread here
https://www.mk5golfgti.co.uk/forum/index.php/topic,121795.0.html as the OP has not so far updated us on his problems.
When the OP of the attached thread first reported his problems my car was going through exactly the same issues and had been for some time. This had never really been a major problem as 95% of the time my wife uses the car to travel the 2 miles back and fore to work every day. On the once or twice that I drove the car and "blew out the cobwebs" the car would enter a temporary limp mode only to regain full power after about 30 seconds or so.
Unlike the other chap who bought a fuel pump I decided that trying the cheapest option first was the way to go. My car is running a stage1 Superchips map and due to the way the car was being used was being fuelled by 95ron unleaded. To try to resolve what was undoubtedly a fuelling issue I filled the car with 99ron unleaded. Suffice to say that for the last month or so the car runs faultlessly and despite trying I cannot replicate the previous issues.
I am only posting this in the hope that if anybody else has this issue they try the cheaper options first before spending out on parts. 👍👍