Erratic RPMs

Hello again, I'm back but this time for my moms van. She called me the other day and said that her van just stalled on her and that her RPMs were jumping all over the place, but later that day it cranked right up and no problems. Then yesterday on her way to bring home my kids she said it was doing it again then called me histaricall and said to meet her at one of the gas station at the interstate with a fire extinguisher that her van was on fire she thought. A gentleman helped her until I got there but he told me that the hood was too hot to open at the time when he got there. By the time I got there I got the hood popped, there was no fire just a lot of smoke and there was what looked to be oil on the ground and some sprayed around under the hood. She said that her RPMs were all over the place again before during and after all of this too. Now me and my husband both have looked and can see what looks to be oil coming from a spot under the hood (I'll attach a photo ) other than this I'm at a loss. My husband and myself know nothing about this vehicle kinda learning as we go, so I have no idea that the part is that is the images. We cranked it up after all if this and no problems other than the RPMs. Thank you for your time once again and look forward to hearing from you.