Mega 18x8,using the Quilt ez robot, Machine will go to the start position and will act like it wants to stitch, Needle will not stitch, makes long dragging stitch/

Quilting is a bit more finicky than regular sewing. Be sure to ALWAYS RAISE the presser foot when threading the top thread. FWIW, I use a separate bobbin case for FMQ that I have tightened the tension to keep the bobbin thread from coming to the top of the sandwich, but I tend to use a finer thread for quilting so adjusting the bobbin takes care of it. In your case, however, it sounds like the top thread is staying under the fabric. I would try tightening the top tension. Also, install a brand new needle--a top stitch, embroidery, or microtex needle seem to work well for me. Test well on a sandwich made of the same fabric and batting and get it adjusted well before sewing on your quilt. Sometimes sewing speed will affect stitches under the fabric, or even on top.

5 Free Motion Quilting Problems and How to Fix Them

Correcting Sewing Machine Tension for Free Motion Quilting NQC

LOOPS Tension or Speed

https://www.generations-quilt-patterns.com/machine-quilting-thread.html

https://www.generations-quilt-patterns.com/sewing-machine-tension.html

https://www.generations-quilt-patterns.com/machine-quilting-tension-problems.html

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TIP: A general rule of thumb is that if the stitch looks bad on the top it is the bottom tension.
If the stitch looks bad on the bottom it is the upper tension. The upper and lower threads play
tug of war with each other.
Tension
You need correct tension on the top and bottom threads, but you must also have correct tension on
the quilt held between the rails. You should have a small amount of "sag" in your fabric. This allows
enough movement of your quilt layers for the needle to penetrate and make good stitches.
Before you start making adjustments to your machine ask yourself, "What changed?" If your machine
was stitching great and all of a sudden it has loopies on the back or puckers, "What changed?" Did
you just change the bobbin? Did you just lift the take up rail? Did you lower the take up rail after
finishing your last quilt? Did you recently change the needle? Did you just roll the quilt?
If the take up rail with the quilted portion of your quilt is too high, it will result in poor stitch quality. You
need a finger tip space between the quilt and the machine bed. Higher will result in poor stitch
quality, too low and the quilt will create a drag on your machine's movement.
Look at your bobbin, a sloppy wound bobbin will not create a good stitch. Make sure that the threads
on the bobbin are snug and evenly wound. Check to see if there is a piece of lint in the bobbin case

Don't know about your particular model, but maybe left is the normal "resting" position. When on zigzag it will move to the right then back to the left. As long as all of your different stitch patterns keep the needle between the limits of the hole above the shuttle and does not hit the machine bed then I would best guess everything is fine.
Hope that is of some help.

Does your machine have a stitch regulator?

What is the brand and model of your machine? Most machines have the ability to move the needle left and right. However, straight stitch only machines will not since they are not equipped to zig-zag which is a requirement for moving the needle left and right.

Are you using a stitch regulator? Try it with the foot control first. More information would help to solve your problem.

Have you changed your needle lately? Have you checked the needle/shuttle timing?

You might check your rear encoder - this is the one mounted to the bottom of the roller base. If it is not making contact or is not plugged in correctly on both ends your machine will have this issue. This encoder could need to be replaced. This mostly affects the regulated stitch mode, but can also affect constant stitiching as well.

Try threading the machine with the presser foot up and see if the loops and snarls go away.........

When the foot is down during the threading, the tension control is closed and the thread cannot enter as it should.

No tension control of the top thread and the bobbin thread cannot connect for a proper stitch.

Make sure the feed dogs are dropped (or feed dog cover is on - I can't remember which way this machine works). The stitch length on the machine has no function so ignore it. (I set it to zero so the machine doesn't have to work as hard). Hopefully this is all that's wrong. If not, use a shorter setting for the stitch length on the regulator, oil the hook and move slowly and smoothly.
Good luck!