I feel your pain.
Most of the time either Rock Auto, or Amazon, informs who is the OEM manufacturer of a part.
On Amazon try searching the reviews for “OEM”, or “original” or “factory part”
Sadly,
just like the Mitsu Zero contained a large number of US or UK invented aero ideas,
Denso,
partially owned by Toyota,
but building many parts for Stellantis,
is the maker of replacement auto parts to default to if Denso builds a version of the part.
They also mix the terminology with matching OEM vs aftermarket parts with quality or performance differences.
