i just found out my valves are floating. when my car warms up it loses power and doesnt redline all the time it just stopes at 7k and pops. when its cold it has plenty of power and redlines at 6800. all the wireing is good and ecu is good. im gonna swap the head to see if that works. i have 2 heads a stock d15b7 and stock d16a6.. witch head is better. and will a d17 head gasket work? i have a b7 block.