I just finished up reinstalling all the external components on the wifes 3.4L and got it started this afternoon. Once it was running pretty good i felt what can only be called a misfire at all engine speeds. Replaced the plugs and wires, checked all the vacumn lines and electrical connectors. This engine isnon-new (read used from a junker) replacement due to a really blown up original. Where do I start to look for this misfire? Thanks guys.