I also just battled the same problem. I changed the MAF and put a stock type filter back in. The problem ended up being just an air leak between the MAF and the throttle body. I put a hose clamp on the fitting coming out the back side of the tube just before the throttle body and the CEL went away... or it burned out. Also to clear the CEL all you need to do is pull the EFI fuse out.