Guys, Your advice is really needed to solve my Integra-B18C irritating probelm. Let me start from the beginning. Last week, I had to replace the cylinder head with a second hand B16A (Honda Civic SiR). The B18C cylinder head was damaged due to the broken inner valve springs (all of them) which destroyed the base of the valve springs and grind on the surface of the camshaft. The B18C cam had the same size as the B16 and for that I decided to use it. Now, the probelm is that the car feel underpower beyond 4000rpm. Another thing I noticed is the car will loss power or decelerate by itself after slamming the accelerator at fifth gear up to 7000 rpm. It will decelerate down to 3500 rpm before the power comes back but this will only last till it reach 4000rpm. This probelm persist unless I put the gear to neutral or back to fourth gear. When it decelerate by itself, I also observed that steeping the accelerator to the floor doesn't do anything. It just keep decelerating. Another is at the time of this first occurence, the speedometer/mileage meter went dead. I'm going to send the car to a mechanic this morning but your opinion is greatly appreciated.