hi to all ive just had an 2000 uk Subaru impreza car drives fine im well happy but when I boost it holds back then goes then holds back .sorry only way I can describe it would appreciate help many thanks

Hi welcome, could be one of many things from a hole in one of the vac lines loose clip on the air box or something more. May be worth doing a diagnostic test either with an odd scanner or using the self test connectors under the drivers side of the dash. http://uk.subaruownersclub.com/forums/topic/2366-manually-reading-ecu-codes/

Try this 1st see if anything comes up. Then I'd have a look to see if there's any loose or split hoses

:Dwill try these steps many thanks  ,,,,,,,,,,,,,,,,,,,,,,,appreciate it

No worries keep us posted as to how you get on, have you got a boost gauge fitted ?

Do you know at what point it's holding back boost/revs wise could be hitting fuel cut point to save it from bad things happening.

I have boost gauge its  hitting 15/18 psi  if it was a normal engine ie non turbo it gives the impression of a plug breaking down  but ticks over perfect ??

its been suggested to me  it could be boost controller ???

Is it standard ? If yes could be the actuator

Over one bar, assuming it's on a standard engine with no mods or remap I'd say it's cutting fuel, turn the boost controller down

thanks for the help will try these and get back to you all :)

If it's got a manual boost controller .... Put it in the bin

it could the the mass air flow sensor had the same fault with mine gave it a clean out its now pulls like a train