A few more details about exactly which model and year you have might generate more responses.
Well, I don't have the intake manifold in yet, so I was going to try to figure this out before hand, but I'm going to go blow any sand out of the intake on the heads right now and start getting it in. I'll be monitoring this thread to see if anyone figures it out.Have you tried starting the engine? Any CELs might give you a clue.