I’ve had similar problems where the thermistor said it was 30 degrees warmer than it actually was. I verified this with an infrared heat sensor. New thermistor solved my problem, probably was a faulty cable.
After you do all the easy checks…like making sure there are no stringy bits binding the filament in the bowden tube, and after checking and maybe cleaning the extruder gear, and trying a different nozzle…I would think that it is likely to be the teflon coupler that needs replacing. They are a consumable item and I have been through a couple.
Had same issue, replaced the teflon coupler. That was causing this issue and the problem was solved!
This is wat you need → http://3dsolex.com/teflon-replacements 27
I replaced it with this one, and the printer prints like a charm
Thanks for your suggestion, I’m quite sure that the Teflon coupler is the problem: I checked everything else and my idea it’s confirmed also by the position of the issue highlighted by the Atomic Test.
I have been fighting on and off extrusion issues with my two Ultimaker 2’s for a while and this thread may have pointed me to a solution that I had not thought of nor tried. Historically I do a lot of atomic cleans, I have replaced teflon couplers, I keep the extruder gears clean, and prior to my upgrade of both my printers to “+” versions I had replaced the Bowden Tubes with “slippier” versions.
What I had not done was use something like the below to clean, and more importantly, lubricate, my bowden tubes:
The difference has been profound. The same print that had extrusion issues printed perfectly with no changes other than adding this filter. I am not sure why I had not done this until now, or in fact if there is some reason that I should not be using it…?