So here is the situation. When I'm at 3/4 throttle or more in 4th gear the turbo feels like it's surging or going in and out of boost. Doesn't do it in any lower gears but have noticed it in 3rd a few times. I believe it's a fuel issue. The engine is fully built 84mm sleeved walbro 525 pump on relay, 6an feed and return e85, ID 1700CC, AEM RAIL, Aeromotive FPR and filter. Precision gen2 6266, 2.5 charge pipe and a 800hp Klm intercooler. Everything is brand new. Tuner can't figure it out. Any thoughts anybody?