Hey y'all, I seem to have a problem after I drive about 10 min. When I'm at idle, my revs will drop/flucuate making all of my lights dim and then come back to normal. What it makes me do is have have to drop it into neutral hold my accelerator down to about 1500 rpms to get rid of it. I believe it to be an air leak. Wear should I look that could cause this idle rev drop? Also I seem to have a misfire problem when I drive at about 60-70 mph. Could an air leak cause this as well?