I have found Walbro OE spec pumps; here is the link: Walbro Products for Nissan SENTRA 1991 4 Cyl. 2.0L. I'm sure some other members who have posted on this thread, e.g. @Y2KG20 or @Chriscar, have more detailed information and may even be able to state whether or not that site is a reputable dealer and/or if the pump is a genuine Made in the USA Walbro.