Hello.. New to this forum. I have a 88 blazer and it just started running really rough. Starts fine with just turn of the key, but soon as i start to give it some gas it starts puttering out like its starving or getting to much gas.
I noticed and fitting coming out of the back of intake by distributor pointing towards firewall. Where does this vacuum line go??

 

Can't help you for where that vacuum line would go, but does the truck run better if you plug it?