yes when you take the oil cap off an mfi setup it will either die or run crap as they have the vacume plumbed into the engine (that is completely normal).

Also that coolent plug thats hanging does that not plug into the grey plug round the back of the engine. take a look in the picture above and look for grey coolent plug.

When this plug is plugged in the revs will die down as the ecu does not know when the engine is hot so its running rich on cold start all the time.