which silcer, what material, what temperature, what layer height, how many top layers, how many walls etc.? There are a lot of settings in the slicer software which could be causing this, I am not thinking that there is a mechanical problem. In the end it could also be underextrusion. Is the tensioning bearing which presses the filament against the filament feeding gear tight enough? That’s one mechanical adjustment that comes to mind. If you are printing at very high speeds perhaps the extruder can’t keep up…
In the different slicing softwares there are a lot of settings e.g. letting you change the order of infill and perimeter printing and also retraction / head lifting options etc. Play with these parameters to get rid of the blobs, play with extrusion rate / temp / speed / nozzle width and other overlap functions in the software to get a smooth finish. Also the material is an issue, some lay down nicely some not so much.
I had a problem with infill not attaching to perimeters at the beginning and there was some options both in Slic3r and Cura for increasing the overlap between perimeter and infill. Remember if you use Cura that there is a TON of options that are not visible by default and you can get the to show by activating them in setup.
Did you build your printer yourself from a kit?
Happy printing and good luck!