Gaps between layers

All of a sudden my printer has been printing objects with gaps in the perimeter layers. I Switched to a new filament but then I switched back to the old filament (which I know prints well) and the problem was still there! Also a small amount of filament started leaking out of the sides of the thermistor and block. I read that the tubing inside the bowden may need replacing so I have went ahead and done that, but have not printed with it yet.

Filament type: PLA 1.75mm (both new and old)
temp: 190
software: pronterface
slicing: sli3er
hobbed bolt is clean
tension is good
print speed is slow... 20mm/s... slow seems to work best for my printer

print with gaps (ignore stringy support material): [drive.google.com]

This is frustrating because it was just working so well. Anything I'm missing?

Possibly a temperature issue. If its cycles too low it stops extruding. This is not always so clear if you have a bowden tube as the filament can deflect in the bowden instead of causing grinding at the extruder. May also be why you print slow.
What control board are you using.
Try to verify the temperature is correct. Experiment with increased temperature to see if it improves. This wont cure the cycling but may stop the jamming and show where the problem is.