Posted this reply in the unsticking VNT sticky in the B5 section, but thought it would be worth chucking in here as well, in case any of you guys can point me in the right direction....
Did this today, thanks for the guide evilscotsman.
It's made a huge difference, but not got rid of my problem completely....
Couple of days ago, car started going into limp mode when under load in 4th and 5th, no warning lights, but would go into limp/cut turbo. As soon as you'd turned car off and on again, all was good until 4th/5th under load. Car also sounded deeper than normal, thought there may have been an exhaust leak at first.
So, checked the exhaust over, couldn't spot anything. Proceeded to take the EGR off (with the help of my bro) and gave it a good clean, as it was really mucky (car has done 215k mind you, 2002 1.9tdi 130 sport). This didn't do anything for the symptons.
Then my brother found this thread, so this afternoon I got hold of some Mr M and set about doing it. For those asking how far the tube goes into the EGR hole, mine went in about 8 inches. Got quite a few squirts of mr M in before I could see it in the EGR hole. Actuator was rough feeling beforehand, but after only a few minutes, began to feel really smooth.
Left it the full 2 hours, which gave me chance to stick a new fuel filter on (try to eliminate that too).
Started up fine, sounded nice, nice smooth idle. Drove gently until engine was warm, then gave it some beans, 2nd, 3rd, 4th, 5th, pulled like a train, complete with LOTS of soot!!! Did this a few times up and down the bypass, just pulled so strong all the time couldn't believe it.
However, just as I was about to go home, I thought "1 more run.." 2nd, 3rd, 4th, 5th, all good, backed off in 5th, then booted again, flat as a flat thing. Slowed down to the r'about, set off back down bypass in 2nd, expecting it to have gone into limp mode but it pulled well again, 2nd, 3rd, but started tailing off in 4th and was quite flat in 5th.
After consulting my technical advisor (brother) we're wondering whether it could be a boost leak, as its only now happening in the bigger gears where its going to be pulling big boost?
Any specific areas, pipes to check? Any other ideas?