I have a 95 accord ex with the f22 vtec motor. I have been noticing as the rpms rise slowly, I hear a weird tick/knock noise about 1200rpm to about 2500. It's usually around town, slow driving. If it's wot I can't hear it very well. Is it normal? I know a guy here in town that has a 94 auto and when you hold the throddle up a bit, you can hear it in his too. valve adj?