I have strings and I have bulging corners. I think lately that I am not going to get this printer tuned in too well for a while. At least I find threads like this one that says I am not alone.
http://forums.reprap.org/read.php?262,649866
What are your acceleration settings and jerk set at?
I just check my printer to see. It says 1850 mm/s move, 1850 mm/s print, 5000 mm/s extruder, 20 jerk. I am sure that last nights tests had 7 jerk once and 8 jerk for others. I also had the move accelleration moved up a bit to amounts ranging from 2500 to 5000 mm/s. I am probably trying to fix one problem and causing another problem. I think I need a log. Maybe I will open up a spreadsheet program and design a layout and print it for my log entries. I can’t remember all those numbers between testing periods. My memory is not that reliable.
That’s at least part of your problem. Default acceleration is 3000, you’re moving at half that – slower acceleration will cause blobs at the corners, so will a disabled jerk setting.
Mechanically;, have you made sure the hot end itself isn’t wobbling in its mount?
I do pull down the jerk myself sometimes, (down to 10), but default accel should be fine for anything but anemic motors.
It might be slightly, to be honest. To be honest, if lower acceleration settings cause blobbing, there must be something wrong with the firmware. Most likely, they have no means to handle filament ooze estimates in the firmware. That seems to be the biggest limitation in firmware. All it needs is a numerical offset number in the firmware to offset flow estimates.
I need to replace my delta rod ends again. I think that is why my effector has a little wiggle.
@NathanielStenzel I have the exact same problems on my delta. It is due to slop in either the rod bearings or the rail/carriage bearings. I’m working on carbon rods and magnets. No slop there 
@Kim_Skotte_Svensson I am using a delta style printer. Are you talking about a cartesian style printer? I imagine slop is slop either way.
@ThantiK I am trying out 3000 mm/s despite the possible wiggle. I will see which is worse, the 3000 or 1850 setting.
@NathanielStenzel Its on a delta printer. I’ve got a delta (actually two, a G2s Pro, and a FLSun delta)
Gonna make delta rods in carbon with magnets and steel balls to eliminate the slop.
@Kim_Skotte_Svensson a number of people like those magnetic balls.