It's fine to use a zig-zag stitch for an even feed foot as long as the foot is made for zig-zag.
You only need to avoid the decorative stitches that stitch forward and backward - the even feed foot won't coordinate with the feed dogs on the machine and the stitching might not look very good.
If you're using a universal needle, switch to a sharp and make sure that the needle is sized correctly for the thread that you're using. Universal needles cause a lot of skipped stitches.
If the needle is too big, it won't allow the friction necessary to create a loop for the hook to catch, so you'll get lots of skipped stitches.
If the needle is too small, it will hold the thread too tightly to create a large enough loop for the hook to catch - although you would usually see shredded thread in this case, too.
One size of needle that can work just fine when you're doing a straight stitch will suddenly be too large or small for the thread when you switch to the zig-zag stitch. The hook will be passing the back of the needle at a different place in the timing, so the thread loop has to be just the right size and in just the right place. Too small or too late and the hook skips.