I have 89 honda civic radiator fluid is going somewhere other than the ground have to add fluid about every 15 miles running badly is it worth it to put manifold gasket on or any ideas what the problem is I think its going in the exhaust

 

Hope you dont have a blown head gasket. You need an intake manifold gasket. A manifold vacuum leak will make your car run badly. I do believe there is a water port that runs through your intake manifold. Have that checked 1st.

 

Try and clean the block then spray it with something to detect the leak. I think athletes foot spray works. Do some searching. Find where it is leaking and replace that.