Question for diesel gurus (strange failure 6.9idi)

mbaird said
Check your oil level . I think that engine has a low oil monitor that will effect how it runs .

Maybe someone installed an optimized idle sysytem on it ? Did you buy it new ?

it’s an entirely mechanical engine, no computer, mech injection. Non turbo.

No, 2nd owner. Has 160,000 miles was only used for towing horse trailers. Bought it last year.