Taelfer

Hi, My Fabia 1.4 is behaving very weird. When I start it when fully cold usually after the night it hesitates to start and the whole car is shaking for 10-15 seconds (misfire!?!?). After those 10-15 seconds car stops shaking and everything is fine. When I start it again even after some time this issue doesn't occur. There is 0 errors. I've replaced EVAP purge valve, because it was leaky. I've cleaned MAP sensor checked current of it's connector and it was 5V. Checked resistance of the upstream O2 sensor and it was 6 Ohm's. Replaced and checked spark plugs recently and they're white now (lean condition doesn't suit them). Oil separator was replaced recently as well. Scan tool shows me that : MAP sensor reads 96 kPa when engine is off and around 26-28kPa at idle (isn't it too low in both cases?). Upstream O2 sensor seems to work fine and fluctuate between 0.1V and 0.9V as expected. Downstream O2 sensor stays close to 0.9V when I'm driving and it gets close to 0.1V when engine braking or at stop (but it raises when at stop). Coolant temperature sensor seems to show correct values. Close to outside temperature when cold and between 85-92 celsius when running. LTFT reads as high as 36 positive from time to time. Usually stays between 15-30. MPG seems to be fine. I've replaced the engine recently (the new one* has around 100.000 km), but the previous one had the same exact issue. Previous engine (I bought the car with....) was burning around 2.5L per 1000km. Not sure how long previous owner was driving with that issue, but could it cause this issue? The cat is blocked? Upstream O2 sensor dead, because of excessive oil burned? And ofcourse the engine has piston slap. Could low compression cause this when the engine is cold? Would appreciate any suggestions.