Mcaple

I have a 1993 sc400 with 170,000 miles on it that I have own every since 1999. I recently left out from my house and notice that it did not seem to shift and had no power..when I got back home which I turn around as soon as I notice I had a problem (about 30 seconds) I notice that there was a little smoke coming from behind the engine. I look under the car and behind the engine as far as I could due to the engine and the firewall being so close I could not see anything. The oil looks good and i do not think i have a blow head gasket. Was thinking a vacuum hose or line pop off or broken. wondering if anyone had this problem or know what it could be. Thanks in advance