Tweak problems

Hi everyone, please sorry for my English, i'm from Brazil.

I have a Prusa Mendel i2, with RAMPS 1.4, Marlin 1.0.0 and Repetier-Host

I'm using 1,5mm PLA and a 0,4mm nozzle.

Extruder in 170°C, bed in 50ºC (40°C after the first layer). 3 loops before the print. 0.3mm in layer height. Auto-cooling enabled. 40% fill, honeycomb. 1mm retract.

I can send my firmware configuration if it's necessary.

My prints are coming out like this:
[drive.google.com]

I know there's a problem with the Z axis (4th and 5th image), but whats happening with the layers in the other pictures?

i dont know much but it seems that you are not using a fan for cooling down the extruded pla . other than this the experts will talk.

It looks like you're printing too hot and/or too fast. Try slowing down, lowering the temperature, or adding a fan if using PLA.

you have the following problems

1 - temperature. your filament is absorbing too much heat. I think lowering your temperature is ok since you have your bed temp on.
2 - Fan enabled - fan helps a lot during cooling down the heat absorbed by the PLA. If your filament doesnt cool down once your extruder pass again to the print, the tweak will be observed and your print will be rubbish.