i have r33 gtst running 11psi with just jap front mount 600x300x76, k&n pod clod air exhaust..etc.
when you floor the acelarator if seems to have a flat spot around 4-5000 rpm then picks up again, feels like its holding back ...but if you let it rev out without flooring it its not to bad...sometimes it revs out smooth ...running 9 psi it feels like it pulls harder and revs smoother.. should i change plugs or the gap...coil packs...
any help... could it be leaning out...