vacuum line diagram??

[86lx]

I have a 97 v-8 explorer,I nee to know if there is a vacuum line that goes under the intake on the back drivers corner on the "t" the one tat is on the back goes to the engine where does the front go? Or is it a plug?My truck backfired once and blew it off and I couldn't find a vacuum line off so I plugged it and the check engine light has been on since.I need a diagram if possible where can I get one?

Thanks,Tim