robinsonracing

I have an 1989 951 and recently shimmed the wastegate and now have a sputter at the top end. The car has chips and cat-bypass. It had a banjo bolt so I removed the jet and it fixed most of the problem but I still have a sputter in the 3/4 boost range and then goes like hell. If I run it through the gears winding them all out, it has less sputter as opposed to doing 40mph in 3rd gear then foot to the floor. I've checked for vacuum leaks (all set). When it sputters, it then lets out an exhaust pop and goes. Any info helpful. Thanks