Looks like you forgot to connect back the IMRC Throttle Cable on the Intake Manifold. Look to the right of the Manifold. Anyway, you must remember having removed this cable in the first place!
The IMRC will pull the cable when the engine starts, therefore the Intake lenghts is shorter and this is why you get this code. Might also affect the idle.
Hopefully your IMRC is still good..! I have doubts if you had the code before you replaced the gasket! Look around on the forum, most of the time its easy to fix (A bit of electronics).
Other than that.. check your connections and vaccuums. I removed the Intake several times and I did get bad hesitation because i forgot some vacuums and connections.