SLIP and TCS light on - 2001 Nissan Maxima

I was just curious if there was someone had a little more insight into what I might be into with this problem:

I have a high milage Maxima and recently the SLIP light indicator has come on, turning the traction control system off. I’m not worried about the TCS being off, although there’s a slight shimmy to the engine when it happens. It’s more pronounced when I’m stopped, and speeding up. What I’m wondering is if this is the result of a bad sensor or if I have mechanical problems, and serious those might be?

Thanks for any help!