2003 F150 4.6:
I disconnected the negative terminal, over the course of two weeks, to complete the following work; new plugs, coils, pvc valve and hose.

Upon startup, immediately I hear and feel a repeatable buzz pattern.
1 buzz, pause, then 2 buzzes that repeat three times, pause, 1 buzz.
This series repeats three times.. maybe under one minute total.

I can’t isolate where it is coming from. Thought radio anti thief but radio is fine, no presets were lost. Thought it was the passenger air bag control but no change if turned on or off.

I am still driving to reset stuff and planning the highway driving today. Rural area so mostly less than 50 mph roads.

My gut definitely tells me something needs reset and this pattern is specific but my searches on the buzzing takes me to engines noises.

Thanks for your review in advance!
Kris

ISSUE RESOLVED: Buzzing was from CD player, it seems to cycling or stuck on a cd. I saw the cd door was moving w the buzzing sound. Buzzing gone after inserting a cd.