Power loss

my cav z24 i am having power loss problems my engine is getting louder and louder and cant figure out why. it is not my exhaust at all i thinkt hat it may be ym manifold. or map sensor

Welcome To AF. How many miles on it ? have you done a complete tuneup on it recently ? how do you know for sure the catalytic converter (cat) is not plugged, your engine is getting louder and you have noticeable power loss ? To me that makes me think plugged cat IMO. Put your hand back at tailpipe and see how much exhaust flow is coming out ,have someone rev the engine a few times to see if it puts out more. why do you suspect map sensor ?It would be handy if you get it checked for any codes as well.