Bottom of the oil pan.
The engine computer is the voltage regulator on a 1991 Dodge.
Yes.
voltage regulator is part of the engine computer
A Dodge B250 Van does not have a mass airflow sensor.
I have a 1989 Dodge B250...it has overdrive
No.
No.
Center of the firewall.
Yes
check the coil , and ecm and all connections
we need more info on this application like what year and what is a b250 i would suppose it was a dodge