I need some suggestions please, my 03 gsi is boosting ok in 1st and 2nd but I sometimes get hesitation on boost in 3rd 4th and 5th. It feels like the boost comes and goes.
It started a couple of months ago, firstly I tried some fuel treatment and some posh petrol but the problem still happend. So far I have:
de-restricted the airbox
changed both BCS's
changed plugs (didn't need it but could of bin a cheap fix)bosch super 4's
checked vacuum pipes (ok)
checked actuater spring (ok but very strong)
can't hear any boost leaks
no warning light and no fault codes.
I must admit on each test drive it feels better than the previous, last test drive was almost spot on but still a bit of hesitation.
By the way as far a I know the car is totaly standard and I don't have a boost guage.
Any ideas would be appreciated plus I'm on a budget so I'm not gonna be fitting bigger turbos etc.