boost dropping sharply from 1 bar to 0.6
 

it seems fine and retards boost to .6.. it just flicks down and holds there...no cel faults at all ..any ideas ??? drives perext otherwise but can feel it holding boost down...knock sensor, maf etc???

Have seen this happen due to a faulty MAF.
Car runs lean and ECU limits boost. No Error codes detected. Only discovered after checking AFR on rolling Road and out on the road.

what year?

cheers scott i am glad someone has said summat..simon its a 1996 gtb...done various checks and no cel, fault codes etc...goes to 1 bar and then back to .6...off the pedal and back on boink 1 bar but a bit erratic....does the maf share with the impreza of same year ??

the code on the maf is 22680 AA271 AND HAS AN ORANGE STICKER...

most likely boost solenoid sticky or actuator faulty.

its a twin turbo and it does it does it on both turbo's..upto 4000 rpm 1st turbo and then it does the same again once over that....

do they both use the same boost solenoid? never looked at a standard GTB boost pipework

dotn know simon, theyre in a box..will have a look !

ok took her out this morning and slightly warmed (but not up to op temp) boosting great and in both turbos..once properly warmed up i get this boost cut..defo think its a fueling thing as it will be getting more fuel on choke..anyone got other opinions...