Hey everyone, I am running into a problem where my car runs real rough and even stalls when at idle...This is all after replaced rear motor mount. Here's what I did, hopefully somebody can tell what's going on:

- disconnected battery (as said in service manual) before removing mount.
-installed new mount, trying to make sure everything was lined up properly
-reconnected batter
-removed 1 spark plug to check its condition, looked OK.
-reinstalled spark plug
-attached spark plug wire...i did have a problem getting the wire to stay tight on the plug, but i squeezed the metal contact a little with pliers to tighten it up. seemed to be on OK, but not as tightly as before.

I'm not sure if there is something wrong with the spark plug and it's hookup, or what. I'm not sure if what is happening is the result of a non-firing spark plug. Would not getting a powertrain alignment after replacing motor mounts affect anything? I appreciate the help!