Got a 2003 Vibe. We replaced the engine with an 05 Matrix engine 2 weeks ago. Runs and sounds like the engine is strong but has a misfire on all cyl. Runs pretty good except idle is kinda rough and after a drive it idles at 2k. I hear a hissing sound when engine is running, not a real loud hiss but it sounds like its coming from under the intake manifold. We changed intake manifold gasket and throttle body gaskets.
What could i do to help figure out the leak? Is a smoke test safe and if so are there any cheap ways to do them?
Thanks in advance!!