Hi guys. Sometimes when i put the foot down in 5th gear the car overboosts to over 20psi, i dont think the car is chipped so should a boost limiter not kick in? the car is aslo hunting now and again on idle.

 

I have the same with my MY2000 Euro. Turbo (218bhp) It happens only when you really working the engine in 4 or 5 th gear.
Probably your boost valve on the left side strut mount that is dirty ( clean with carbu spray ) or the cold wheather : better for the engine...

 

Is it decatted?

 

My car has a Unichip, a full exhaust from scorpion, Samco hoses, Forge dump valve, and the max boost (working the engine in 4 or 5 t gear) is normally 1.25, but sometimes it goes to 1.4, I think its the cold weathter.