basically I got a different ecu and have been reving a little higher lately and I suddenly feel like my car has lost a ton of power. I feel like I have no top end but all my bottom end is running fine but once I'm in vtec it seems I have a lot less power than a few days ago. I was wondering if it could even be my piston rings. the head is stock at the moment. and its a 00 civic si with b16a2

 

compression test.

If that shows trouble, leakdown test.

 

how much higher is a little higher? look if you have no problems at idle then you don't have a bent valve. however you stand a good chance of damaging your camshaft or lifters if you spin higher than 9 grand on stock valve springs and retainers. this is known as floating a valve. basically your camshaft is spinning so fast that your valve springs cannot hold constant pressure against the cams so when the crest of the cam opens the valve by the time the crest spins around again the valve is still open and the crest of the cam slaps the lifter. if you don't have any problems with excessive smoking out of the exhaust then you don't have any problem with your botom end. you can also check your compression to see if you have any problems with valves or the bottom end