Printing getting worse
So i've been printing with this PolyPLA filament red. It's printed okay alongside several other cylinders i've printed. So i know the model works perfectly as I have 6 other prints that came out just fine.
However, on this red, i'm getting worsening layer failures. Initially it was just a few layers had missing filament making gaps in the layers but still holding. Now those structures are severely weakened at those points I know. Luckily they're closer to the edges so it's okay if I lose those layers if it pulls apart, however, now it's getting more and more failure. The model is around 70mm tall at final print. The first one printed with layer failure 3 times. The second failed completely at around midway and didn't push filament. Now, it's lucky if the first layer even completes properly. I've gone through recalibration, refeeding the filament, checking for a block, cleaning the heatbed and nozzle after each print, but it keeps getting worse. Any ideas for me to look at? I could tear the entire nozzle casing apart and clean everything but I'd like to avoid that if possible because I know that's a time consuming and tedious job with one set of hands. 
RE: Printing getting worse
How about trying an another roll of filament? The good prints do look quite bad in my opinion too.
From the look of first part it seems that filament is not pushing through.
1.The PLA is sensitive to low print speeds. Print too slow and nozzle will clog.
2.Filament may have physically incorrect size, be too thick, too thin or even have "bulges".
3.The tension spring which is pushing the feeding gears into the filament might get loose over time and the machine may have no enough grip to push it through.
4.The filament roll is tangled, too heavy or otherwise refuses to rotate.
5.I do assume You did set temperatures correctly?
6.When You remove the blocked filament, is there the visible "bite" in it where the gears should push it? If Yes, You may need to clean those gears with a needle or something so that they can grip the filament again.