Kojot

Hello Octavia drivers! I have 2005 Octavia II 4x4, 2.0 FSI (BLX). From a few months I have very unusual problem while driving and till now no one can fix it. If I go slowly for ex. on 4th od 5th gear and about 1800 rpm, seems like engine tugging (not much), feels more like something wrong about wheel or tire (but checked in service and all 4 wheels and tires are in perfect condition). When I go faster (90-100 km/h) and release the accelerator, between 2400-2100 rpm feel litlle vibration and appears hum in exhaust (not so loud). After 10-15 km when the engine temp. is already 90°C and I go fast (90-100 km/h) and release the accelerator, there is no cut-off! Looks like accelerator is little bit pressed and display on dashboard shows fuel usage 2-3L/100 km instead 0,0L/100 km. When I press accelerator feel no power and fuel usage shows 30-40L/100km, but from time to time it returns to normal, but again when I release accelerator there is no cut-off, when press no power. The worst is when I drive up hill. When I slow down and go for few minutes about 50 km/h everything is back to normal (just tugging a little when go slowly). When I go faster, everything wrong is back again. The warning lights on dashboard don't light up. Checked all in few services: there are no errors, engine works good, all engine parameters perfect. Done: cleaned throttle (+adaptation), cleaned intake system + valves (there were not much carbon in fact), new valve cover with PCV, new clutch position sensor. No one can find how to solve this problem. Does anyone have an idea what it can be?