Filament extrusion skipping? - Improve print quality

I keep having this problem where it prints perfectly but I feel like it is missing extrusion points. I can manual extrude as much as I want and it never skips.

I have a .35mm hot end. I am using Pronterface and Sli3r
Some of the settings, (let me know if I miss important ones)

Layer height (mm): 0.2
Perimeters: 3
Solid Layers: 3
Fill density: 0.35
Nozzle diameter: 0.35
Filament Diameter 2.75 <-- I measured this with a mic
Temp: 220C

Print Speed
Perimeters 30mm/s
Infill 60mm/s

I think everything else is left at its defaults.

You guys have been great in the past, thanks ahead of time!
enob

What firmware are you using? I know Marlin firmware has a "safe extrude" temp. which will prevent the extruder from pushing filament if the hot end drops too low. I've run into similar problems if I try to print too fast or with the fan on too high.

I am using Sanguinololu electronics with Sprinter firmware. I have the temp at 220C and I thought that was normal for ABS.

Just another thought. Maybe my Pololus stepper driver board for the extruder is overheating? Does that sound plausible?

I was monitoring the temp for the extruder during the print and it was right on target. I don't think that it would even start printing and stop randomly if it was hitting the safe temp.

I've not done anything with abs yet so I'm not expert but it looks like your not putting down enough extrusion. I can see that the perimeters are not solid. Have you calibrated the extruder? My theory is that if you are not extruding enough material when printing slowly, you'll get breaks when doing quick infill. Also, make sure you are using slic3r 0.8.4. The previous version had some nasty bugs in retracting and de- retracting.

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Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9

Okay, I will double check that when I get home. In the mean time, are my settings close? Is 0.2mm a typical layer height for a .35mm nozzle?

I don't have a 0.3mm nozel, mine is 0.4mm but, as far as I am aware, 0.3 is ok but I'd go to 0.2.

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Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9