Passap machines are sturdy but they need regular maintenance, especially if you haven't used it in a while! Weird noise combined with badly formed stitches is often a sign that something's shifted or there's dust/fibers stuck in the mechanism. I'd suggest first cleaning all the moving parts thoroughly with a soft brush, checking that the needles aren't broken or mispositioned, and making sure the carriage slides smoothly on the bar. If nothing changes after that, then yeah you'll need to have someone who knows these machines take a look at it, because Passaps don't adjust easily if you're just tinkering with them on your own!