A little help from the ones in the know. 05 650L with JD jet (165, stock pilot), UNI filter out of the air box and smog removed, stock pipe unbaffled, Clark tank, sealevel in Florida. At constant throttle, 1/4 through 3/4, any gear any speed I get a surging. Enough that it feels like brakes are being applied softly over and over. Pulls strong throughout the band, gobbs more power that stock. No stumbling off the line or hiccups during accel or decel. I've searched the forums and can't pin it down ? lean condition (jet too small?), air leaks (no popping through exhaust), UNI too restrictive (in the open air?). I'm way worried that this is hurting the engine - any help is appreciated.