Ok so yesterday i drive the car with my brother im in third i step on it, and it revs to 4k and starts to bog so i shift to fourth and it does the same shyt. So i get home and we check the time and it was too advanced so we brought it down back to stock. And it started to run better. Only thing was that at idle if i tap on the accelerator to quick or too much i bogs and shakes for a second then the revs go up. Now i was coming home from school and the car doesnt wanna get over 4300rpms it just cant for some reason. So now its doing what it was doing before and the idle thing that its started to do. What could be the problem. Spark plugs are new, oil was changed recently, and the engine is really clean. Only thing i can think of is the exhaust, i have it open pretty much. Its the header, gutted cat, resonator, and no tip. But i ordered one already, but i still dont know if that is the problem.