I am running a 034 Motorsport stage 1 tune and everything seemed to be running fine for about a month. I’ve just started noticing that power seems down - I have to floor it to get any decent speed on the motorway and is not effortless like even in a stock tune.
I went to a long drive and got a drive system malfunction light come on and turns out it is the p0299 underboost code. I pulled over and cleared it with VCDS to see if it would come back. After an hour, the check engine light never came back and did another scan with VCDS and no fault codes popped up.
Where should I start my diagnosis? I checked the coolant level and they are normal. Is it the diverter valve that needs replacing?
u/Low_Statistician1644 — 18 days ago