strange ratat ta tat engine noise

2006 dc tacoma 140 k
K my truck sounds like a diesle its driving me crazy . Does it in neutral while slowly reving.
Does it when I maintain a steady speed . Goes away when I accelerate hard or when idleling . Had my truck for a year and never sounded like this never . I had a timing cover replaced by the dealer ship a month or two ago and now this knocking is pissing me off
I've spoke with a few tecks and they can't really tell three thing they said were the crankshaft bearings a oil pump or a rod

Can anyone share their expeince with any of these issues?

All I can do is turn up the radio

 

Make a video of it and post it here.