Tension problems top stitch is irregular it seems slanted the bottom of the material has loops where the stitch should be i have a singer 7462 touch n sew ive made about fourty quilts on it and it's never had a problem before the stitches were perfect i know it's the tension just dont know how to fix it my four year old went to work on the tension dial today now it dosn't work when i dial it it's the same and this maciene is supposed to be auto tension =( if anyone knows the fixit please let me know my maciene is not clogged with lint i cleaned it, changed the needle and use good thread, dosnt matter if it's nylon or cotton it still does it it's oil is fine and it seems to work fine with the decrative stitches just having problems with the straight stitch the legnth works fine , but no matter what size stitch i use it still has slanted top stitch with loop on the bottom, i can pull the stitch out by just tugging on the leftover thread that is where i start the stitching

Be sure presser foot (embroidery foot) is fully lowered or tension discs will not fully mate. There should be notable difference in tension with foot up verses foot down as you pull on top thread?

If the bottom thread is tight there should also be loops on top and this means that the upper tension is too tight.
Get out your manual (http://www.singerco.com/uploads/download/1198_8763-efs.pdf) and turn to page 24. Under "ADJUSTING TOP THREAD TENSION" it tells you that if you're having thread tension issues, change the tension control dial on the top of your machine from auto. It also shows you a diagram with your problem illustrated on the right side of the page. The bobbin tension is set at the factory, so all tension problems can be solved with top tension adjustment. Set it manually and if it loops on top, loosen the tension a little. Test again. Repeat until loops are gone.
Using different colours on top and bobbin and a contrasting fabric (e.g. black top, white bottom, light blue fabric) means you can easily see what's happening. A perfect stitch is when you see exactly the same stitch pattern on both sides of the fabric. On top, the bobbin thread colour appears between stitches as a tiny dot and on the bottom, you see the top thread dot between stitches.
If it's impossible to get the tension right, take it to a technician, because it's a sign that the hook timing needs attention.

In two words, this sounds like a problem with: thread tension. Quite possibly to the point of having an entirely mis-threaded machine, whether because the thread was not routed correctly, or because parts of the thread path are missing.
(Let's review - just for a sec - the basics of how the stitch is formed. The needle, carrying the upper thread in its eye, penetrates the material. When below the material, the needle begins traveling back upward, creating a loop in the thread. (Depending upon the type of machine, either a hook or a shuttle) then pulls this loop so that the lower/ bobbin thread runs then through it. Then, as the needle retracts further upward, an arm (between the tensioning disc/spring and the needle thread path) pulls upward of the thread, tightening the stitch into place.

If, for example, there is no tension at the tensioning disc/spring, that arm will take from the thread spool instead of tightening the stitch into place.

the looping on the bottom usually is a tension problem, the top & bottom tension are unequal usually fixed by adjusting the top tension.
some people that I've talked with have had success with changing to a different size needle ( depends what type of thread is being used).
when the machine is threaded the foot needs to be up ( this releases tension on the thread), when the foot is lowered it the tension is set on the thread. if the material being sewed is too thick it raises the foot too high & releases tension on the thread ( the material has to be really thick to do this).
if there a piece of thread or lint in or around the tensioner or bobbin area it could cause trouble.
other wise if you've tried everything you can think of, take it back th the store & have them try it & tell you what is wrong.

also this machine has bad reviews (i'll provide a link so you can read them), people having the same problems as you are. the newer singers just don't seem to be the same quality tha the older ones were.
all bad reviews
http://www.amazon.com/Singer-5400-60-stitch-Sewing-Machine/product-reviews/B007ZG9DTQ/ref=cm_cr_pr_btm_link_1?ie=UTF8&showViewpoints=0&sortBy=byRankDescending
mixed reviews
http://reviews.walmart.com/1336/20573406/singer-5400-sew-mate-60-stitch-sewing-machine-5400-reviews/reviews.htm

I have a simple and I have better luck when I use a SA156 metal bobbin. Another thing, has she watched the cd that came with the machine? This machine is a little touchy as far as threading goes, I have been sewing 50+ years. Usually, it is in the top threading that causes the problem. If, she has a question, she should call Singer at 1-800-4singer and they will walk her through all of the threading and other troubleshooting strategies. Good luck. Hope this helps you.

Is it looping on the bottom of the fabric? If so this is a top tension issue, you need to check some things,

-make sure you thread the machine with the pressure foot up ( this allows the tension discs to open up so you can pull the fabric away from the machine with the foot up and allows the thread to get to bottom of the tension discs)

-make sure your tension settings are set to the medium setting. (Usually 4 or 5)

If this still does not help, then turn the top tension knob up (from 5 to 6,7,8,9....)

-If that still doesn't do it, your probably need the tensions reset. Let me know if you need more help.

-Chris

FYI.. Loops on the bottom, problem is on the top..
Loops on the top, broblem is with the bobbin.

pucker is caused by too loose or, to tight adjustment of: the thread tensioners both the bobbin tensioner and, the needle tensioner need to be adjusted: to adjust the needle tensioner turn the side knob clockwise is tighter counterclockwise loosens; the bobbin tensioner is a tiny screw on the bobbin holder adjust both tensioners until your stich loops' both top and, bottom are tight but, the machine does not break the thread

By saying the tension of the foot is good I take it you mean the pressure is set good. Maybe add more pressure. Are you sure that the lever on the bottom right is set for sewing and not darning which raises the needle plate above the feeddogs? Sure that your feed dogs are moving well at the stitch length set. With slippery fabrics you may need to try a different type of foot. There are some plastic or teflon coated ones that will not stick to or hold the material back. Or try a Walking Foot or Even Feed foot which will move the top of the fabric evenly with the bottom.
They do help alot.
Good luck

Sounds as though you've misthreaded the upper tension. The best way to verify this would be to thread your machine, lower the presser foot on to the material. Now try pulling the thread through the needle. (Assuming your upper tension dial is set to a number greater than one). You should feel resistance. Should you not feel resistance, rethread your upper tension.