stock injectors??? running out of fuel. blown engine in your near future. post all the code #'s b/c i'm not understanding what you mean by manifold code unless it's manifold absolute pressure and then that's your mapsensor.

sounds like you have quite a few issues that need to be fixed before you can point the finger @ a vacuum leak.

get larger injectors, chipped ecu, and tune too once all the issues are resolved.