Hi, Yesterday my mini had hardly any boost felt like it was just running on engine power. Today i took it for a drive and the boost was back.. then parked the car for around a hour and went back out for another drive and now there seems too be no boost again.. Its also not showing no codes.
What could cause this problem?

Its a cooper s 2011 n18.
Mods: Bigger intercooler, De-cat, full milltek exhaust, panel filter.

Thanks kieran

UPDATE:
I have checked all vacuum hoses and all of them seem too be ok. Also checked all cold side pipes from the turbo and intercooler all ok and tight.

Went too check the DV and one of the bolts would not come out so i could not check that...
I am still not getting any codes or engine light.

Need to check for BMW/Mini specific DTCs (diagnostic trouble codes) You will need a BMW/Mini specific code reader to pull them.

I think i got you.
Part cost around 150euro and its that.
Solenoid valve....!!
Im almost 100% sure that is that if you have NO leaks!
Its something that its not coming out as a fault on any diagnostics(its pretty rare went out as a fault)

The bluetooth OBD2 are $10 and you can hook it up to torque lite and check your boost in real time to see what is actually happening.
Edit* and see pending faults.