I have done a ground up rebuild on a 1991 crx si w/ d16a6. I have a lot of lag when I drive the car. But not when applying throttle at the intake. My #1 cylinder seems to have the best spark quality & is the cleanest plug. #2 is slightly dark, 3 is worse & 4 seems to be almost black. I am going to change plugs but I am trying to get to the root of the issue. Possible rich fuel ratio? The ignition timing is right on 18 degrees. Any suggestions beside replaccing distributor, ignitor, etc.