Yeaterday my boost pipe popped off and managed to get it back on but was running rough and banging on boost. So i left it overnight and went to drive it today all seemed fine until i tried putting my foot down. I cant get no boost. The needle barely moves off the stop on the boost gauge. But have managed to get it to boost abit on some occasions but not 100%. What could this be? Iv had it on snap-on diagnostics with no faults.