I have a bit of a boost issue, it only happens once maybe twice when the car is cold. Basically on partial throttle in 3rd and up I get a boost spike, the car feels really hesitant and then all of a sudden the boost gauge goes into the red then backs off again. As said it only does it once or twice and then its fine for the rest of the journey. I have changed the boost solenoid but it hasn't helped. Any ideas guys.