Sub in my daily driver????

i have this sub in my daily driver, which is an 88 4runner, its in a ported box and it sound pretty good. BUT that year of 4runner the top comes off, and now thats it hot out i took off the top, and now i cant even tell the sub is hooked up. Is there anything i can do? Can I just plug the port and make it a sealed box. Or would it make a differance.