Newbie quality issues help

Hello all, newbie here. Zero experience with 3D printing, haven't seen one running other than online, so every bit of it is new to me. I've scanned through the troubleshooting page photos and didn't see anything that looked like the 2 issues I'm having. I suspect I just don't have something set right, but not knowing what to check, I'm not sure where to start first.

Two issues I'm trying to resolve. First is on infills. It looks like part of it is lifting up or not sticking to the previous layer. I'm using PLA at 220C, using slic3r for the code on a Prusa Mendel with a .35 nozzle. First layer is .35 (maybe .4, can't recall at the moment), then using .25 for the layer height. Table is at 60C. My infill was set to .9 on this sample.

Second issue is every so often, it's like the material shoots in a different direction. See the edges on this photo.

Any advice on where to start tuning? PLA is brand new from a reliable vendor, according to the forum.

It looks like underextrusion/extruder jam.

If you have done all the calibration, you can check:
Idler tension.

Extruder motor current, if it is too low it will skip, and if it is too high the thermal protection in the driver will kick in, and cause the motor to skip.

Extruder temperature, best way to check is to stick a thermocouple in the hotend where the filament normally goes. 220 degrees should normally be more than enough to melt PLA.

Gunk on the hobbed bolt, so it can't dig into the filament.

Filament getting stuck in the hotend tube, but then you wouldn't be able to finish the print.

If you haven't calibrated the printer yet, there's a nice guide here: [reprap.org]

Thanks Ralf, I spent some time with it, trying to see if I could resolve the issues and I can't seem to get the filament to feed consistently. I'm using Pronterface to tell it to "extrude", so 50mm or so. I put my hand on the filament and it's feeding, then it'll skip, then feed, then skip. I've tightened up the tension roller that pushes the filament against the hobbed bolt, while it's running. I tighten them until it stalls out, then I back off and keep backing off and nothing seem to change it or make it feed smooth and consistently.

I've taken the hobbed bolt out and cleaned it twice now, but as soon as I put it back in, tell it to extrude, then it slips and cakes up the hobbed bolt again. It's almost like it's trying to feed it faster than it can extrude, but I have no factual data to suggest that's what is happening, but I can't think why else I can't get it to feed consistently.

Any ideas or suggestions on what to check next? Do hobbed bolts wear out?

You may want to clean your nozzle. New hot ends tend to have some metal fragments from fabrication left inside the nozzle. Symptoms are reduced filament flow and these 1-2 sec jams you describe.
To clean the nozzle: heat it up to working temperature (190°C), then switch the hotend off. Wait for it to cool down to about 80-90°C (depends on your filament, you may have to experiment a bit). Then pull the filament out slowly.

If you did everything right you should be able to pull out all of the PLA in the nozzle at once. The PLA is still soft but not molten. This will remove any particles that may be insinde.