golf n reg tdi power loss issue

[scoobydoo]

Hi, I have a n reg tdi 90 golf estate that is sufferring a power problem and am desperate for some help!!!!
when i drive at speed and pop my foot down i feel the power come on and then it disappears and stays kind of constant revs. when you go to over take the car accelerates and then all of a sudden power drops.  tends to be under full throttle. have done a fuel filter as thought it was fuel starvation but didnt change please any ideas ayone??

[boneybradley]

check all the hoses (especially the intercoller one's) as it sounds like one of these are leaking/compressing making you loose boost

oh and i'm unsure if this engine has an n75 boost valve but there common failures on later golf's/passat's

[scoobydoo]

thanks for those pointers will have a look tomorrow. I thought it is either a breathing or fueling issue. what sort of cost iis the boost valve and are they easy to change? this motor is my daily lugger that looks like a shed so i dont want to spend afortune on her!!!

[*tell*]

i had a problem with mine when i scanned the codes it came up with 00575.
it relates to boost pressure. it turns out the the wastgate on the turbo had sezied
this normally happern @ 70ish mph. i removed the turbo free the arm up and it been fine
since 

[MK3TDi1996]

oh and i'm unsure if this engine has an n75 boost valve but there common failures on later golf's/passat's

My N75 valve ticks like a clock on phet - good/bad?

[scoobydoo]

went for a 300 mile round trip up motorway last night in it  - seems to be getting worse - when pressing the go pedal it seems to surge the power on and off as if turbo winds up and cuts out then winds up every couple of second -when you accelerate hard it gives a shot of turbo for about 10 seconds then you feel it drop but if you take foot of the pedal and plant it back down again it comes back for another 10sec go. fuel consumption gone

 up plenty to fettle with this weekend!
thanks for all the pointers