B16a2 vibrating.

[Babar Firasat]

I have an honda civic type r ek with b16a2. When I bought the car, it was fine. I changed the induction kit on it, k&n, and exhaust manifold from 4-2-1 to 4-1, I changed exhaust gasket with it. Added more ground wires. After that the car has been showing problems.

 So the car started to loose power all of a sudden when driving and the power would come back, even in vtec, same thing would happen, sudden loss and regain of power. Then one day, one cylinder stopped working. Some of the valves were burnt off. Mechanic changed 4 valves, timing belt, tensioner, water pump, spark plugs. 

2 weeks later of getting it, same thing is happening, sudden loss of power with vibration. What could it be?