Hi all,
right my car has been running fine and boosting perfect up until yesterday. When idling it miss fires slightly. When im boosting, the tubro spins up and the boost gauge rises but the car feels like its pulling me back, then it after about 4k it will start trying to pull .Now there is also an irregular tap from under the rocker???

I have no idea what it is, the oil pressure from cold is about 60-70 psi, when warm falls between 40-20 psi. I put 10w/40 part synthetic oil in.
Not sure whether this is relevant, but thought i would tell you incase.

Please help!!!!!!