Can any one help? My car has a tendancy to underboost at 0.5 on the boost guage, but sometimes i get lucky and it works at full boost. Ive had a boost test done where all the pipes were checked and wastegate but all are working fine. does anyone think there could be a problem with the ECU? email me for any answers.
James Tombs.

 

James,

I take it this is 0.5bar ?
If so it maybe the actuator arm needs a little retensioning.
Had a boost problem not to long ago where the wastegate was blowing open under heavy boost. Retensioning the arm solved it

Pete