Hi all, Can anyone help I have a 2008 impreza 2.5 sti. The car has been remapped and runs really well BUT every 3/4 days the car loses boost and runs flat. I have replaced the dump valve because I found the piston was sticking (standard). Once boost drops off I found that if I disconnect the battery for approx 1 hr once reconnected boost comes back and runs fine again approx 4 days later boost drops off. Possibly when sat ticking over for 5 minutes or so ??. Please has anyone have any ideas what the problem/cause of this fault could be.. Thanks.