Ok thanks everyone for your time on this and repsonces so far! Right had an interesting weekend trying to sort this issue, I *think* im closer to finder the problem... Took it back to the remap guys and they spotted the issue, but couldnt find the cause.. They went through the remap figures i.e requested and made boost and they are as they should be before the surge or hesitancy starts. They suspect either coils or MAF. They checked all my breather pipes, checked my filter and intercooler pipes and no splits in it what so ever.. They've offered me a full refund for my remap, but I really want to find the cause of the problem if I can before I do this as i believe it's not the map now.
Firstly I put my standard N75 valve back in as you guys said and its doing the hesitation again... So as advised I bought a standard DV from Audi thinking it could be a problem with my Baileys one... Unfourtantely it was no different, and the hesitation came back!
So least I can rule my DV out of the equation, very frustrating though!!!!!
HOWEVER my friends came down with VAG-COM and he offered to hook it up and go through the values while I was on a run which was we did... Results were interesting!
He checked the Air Mass values or g/s value to see what it was making... My maximum I made was around 190 which I think is about right for a chipped car, before the hesitation started???
Anway here's the interesting bit.. When it started to hesitate he was watching and logging my cylinder missfire log which was group 015 and 016 I believe and it seems that the hesitation I'm getting.. IS ACTUALLY MIS-FIRES!!!! When the surge began cylinder 2, 3, and 4 all started to miss-fire and the figures were quite worrying like 3 - 4 on each for nearly 10secs and it'll struggle to accelerate but then find boost and acceleration again and they'd all clear.. (which is the hesitation I've been talking about) My friend actually said it feels exactly like it's overfuelling and obv the sparks aren't burning the required amount of fuel and hence the missfire... I've logged this on vag-com so if anyone would be kind enough to look at the log, please let me know and I can email them to you for your opinion.
So obvsiously the question now is what's causing the mis-fires? Can it be the coil packs or another faultly sensor causing it to overfuel like it is?? As far as im aware the coil packs have never been changed since 01, but I had changed the sparks to NGK Laser platinums when I first got the car on the service. At least now I know the hesitation is actually mis-fires and not my turbo acting up which is more of a relief...but still very frustrating!!!! Whats bizzare is they only missfire when they reach optimum boost it'll seem, and on tickover and normal driving there fine. I thought if it was coil packs, they'd be missfiring ALL THE TIME?? At one point all the cylinders has misfired like 4 times each continiously until the hesitation had gone...
BUT, the most frustrating thing for me is WHY DIDN'T MY CAR LOG THESE IN THE FAULT MEMORY AS A DTC as it should do when it detects mis-fires and flag it up when I check for errors? Whenever I check for faults it keeps saying NOT DTC's found!
So yeah, would really appreciate your comments please from anyone who's had the same issue, before I consider spending over £100 on coil packs! Thanks