On my 94 GSR, I just added an Apex N1 exhaust. After I put it on the check engine light came on. I asked some friends and they told me to disconnect my battery and that the CPU just had to sense the new settings. Well that didn't work and it's still on and I don't have the money right now to take it to a mechanic. Anyone got any other suggestions on how to make it go away?

Now same car but everytime I drive it or rev it there's almost like a grinding noise or something when it's between 3000 and 4000 rpms. I thought I just a rock in my intake but I cleaned the filter and it's still there. This one has stumped me and all my friends so I'd appreciate any help cause it's bugging the hell out of me! (it's really loud!)

Thanks