Hi guys,

my type-sa is acting funny. It has a tdo5, uprated top mount, 440injectors, 225 fuel pump and a few other little bits. the problem is when i put my foot down it pulls fine to 1bar (boost spike) then settles at .7bar, if i keep my foot down the boost then starts jumping from .7 to 1bar. it just goes up down up down until i changed gear then will do the same again.

I have been told boost controller will solve the spike but i want to know whats causing the boost hunting thing.