How do I Know which cylinder is #7 ON A FORD, F-150 4.6 ENGINE?

What is your question?

REPLACED THE INTAKE MANIFOLD, NEXT DAY TOOK IT TO THE DR. OFFICE RAN FINE. WHEN I CAME HOME IT STARTED MISSING AND CHECK ENGINE CAME ON. NEED TO NO WHICH CYLINDER IS #7 SO i CAN CHECK IT.

What makes this problem better or worse?

ALL THE TIME

How long has your 2008 Ford F-150 had this problem?

SINCE WE PUT ON THE NEW INTAKE MANIFOLD