During normal cruising at speeds below 55 the engine feels as though it gets a bit of lag or stuttering. This is an 02 stock wrx 5mt, 130K miles, with constant maintenance and regular mobil 1 oil changes. It doesn't have any codes. I have searched on here and can't find a similar issue. The rpms don't rev to lead me to believe it to be a clutch issue. The boost gauge doesn't spike to lead me to believe it to be a turbo issue. I changed plugs at 112K. Any other thoughts?