I had an issue like that as well, from what I've been told you can't use leather needles on vinyl. I went down to a 135 #18 needle, I think they said thats the smallest they come in for industrial/commercial machines, I haven't had a problem with that since. But keep in mind your thread size, upholstery thread may not fit in an eye that small. I think i have #69 nylon thread and its ok.
Here is an interesting link on leather needles
I have to go to an upholstery supplier for my needles, I'm pretty sure you can't buy these just anywhere.
Groz-Beckett is the brand I use I know singer makes some. I think this will help send you in the right direction.