First things first. I Bought a 98 civic ex turned out they swapped out the y8 with a y7. So i just recently did the swap back and put in the d16y8 and ecu. Im running one code for the crankshaft speed fluctuation sensor. but car ran nice for about a week then started to get the p0505 code for the idle air control system. I did the idle relearn and turned the idle adjusting screw to get idle right about 750-800 rpm and the code hasn't returned since. But now it feels like i have a huge power loss and i cannot find any vacuum leaks anywhere. I hooked up my friends scanner tool that reads the live data stream and it said my manifold absolute pressure was at 7.5-8 in. hg at idle and normal operating temp. .So i have looked everywhere to try to find out the normal manifold absolute pressure readings and everything keeps bringing me to the map sensor. So im going to ask here and I am a newb to the forum so bare with me. could this be because of a leaking intake manifold gasket?

 

Why haven't you fixed the CKF sensor code? Start there.