changed. aic motor and fuel..low oil gage won't light up unless cranking on 1993 Dodge Ram Van B250

Need help before I just buy the fuel pump, I did the above and a fuel filter and air filter..backfires and makes a loud hissing noise before it dies..runs when pouring gas in carb..+il guage drops and red lighT when key is on..only shows pressure when cranking..will run barely after sitting for a day..

Asked by for the 1993 Dodge Ram Van B250
the oil light while cranking is nothing more than a bulb check. that is the way the system worked at that time.
before you do the pump, check the fuse and see if it is blown. even if it is, the pump may be drawing too much current.

Oil guage shows no pressure unless cranking and then drops..fuse good to fuel pump..going to change the relay now..hope the oil pump isn't bad as well...guage rises and then drops...