Have a low mileage 2016 Q5 TDI that was running a little rough at idle so I had the intakes taken off and the EGR solenoid replaced. Before the work we just had an EGR temp sensor check engine light on. So had the intake and EGR removed and found tons of black tar built up around all of the intake parts. Everything was removed and cleaned to like new condition and then a new EGR valve installed and everything put back together. BUT, now its running even worse and idling rough. The original check engine light has went away but now I have a cylinder 3 & 4 Contribution Balance check engine light errors P0269 and P0272. Seems odd that I would suddenly get both of these after all of the repairs and sensors were replaced. Thoughts?