I replaced my valve cover gaskets on my 2001 xterra v6 over the weekend. Had to remove the upper intake manifold as well to get to the driver side valve cover. I replaced the spark plugs while I was at it.
Started it up and it was fine. Two days later it has a rough idle at stops and in reverse. I replaced the upper intake manifold gasket when I removed it. I did not replace the what seemed to be one time use manifold bolts. Some of the hoses were cracked but I didn't break any of them to remove parts.
I want to say its a vaccum leak but from where? Would not replacing the manifold bolts cause this?
Any ideas on what it might be?