My car has developed a strange issue when on boost.

It seems to be holding back at about 5k upwards.

Its not a missfire or that as it doesnt splutter but just seems theres a lack of power and you can feel it not wanting to pull.

All ignition components are new and the fuel is v power as it has always been.

I have logged some data and compared it to my last run when the car was going better.

According to the log it is not pulling timing as it is the same across the whole rev range.

AFR's seem in check 11.3 then finishes at 10.8

The only 2 things that are different is knock is slightly higher earlier in the map

(value 31 at 4.8k then drops to 16 or so on the rest) so it may well be that but surely that would show on the timing log?

The other being that the boost is erratic.

In my earlier log it is 1.7 all the way feom go then tails off to 1.63 near the limiter.

My recent log shows 1.7 then immediately dropped to 1.66 at around 4.8k and then 1.65 at 5.2k then its away down at 1.58 at 6k.

I have checked all hoses and they are secure with no leaks etc.

Just wondering if it may be the bov valve.

I know they are usually bombproof but is there any way to check it?

Thanks.
