Slewz

Hi looking for any advice on my car it’s a 2006 56 a3 sportback 2.0t fsi and every time it hits 4000rpm the Rev counter jumps up and down the epc and engine management light flashes the car feels like it hits a limiter I’ve removed a forge diverter spacer and swapped out the diverter valve to a revision D model, can anyone shed some light? thanks in advance

Hi new to the forum just recently bought a a3 sportback 2.0t fsi S line 2006 56 plate in lava grey, I’m looking at changing the diverter valve later in the week as it has a slight issue when it hits 3500-4000 rpm the Rev counter jumps up and down and epc light and engine light flashes??