I just saw an article that suggested putting a small piece of mole skin on your machine just above the needle. They put sewers aid on the mole skin so the thread would run across it right before it goes thru the needle. The also suggested trying a topstitch needle if the metallic needle wasn't working. This was for sewing with metallic thread. I haven't tried it yet but it could help. I have also seen people suggest quilting with a denim needle. Good luck
Also did you recently break a needle? Is there a small nick on your throat plate? If so get some really fine sandpaper and remove the burr.