So my sister has owned a 2000 Nissan Xterra since it was brand new. For the first time ever it has absolutely stopped working. BOOM just like that, crapped out. Since I have been around automotive shops long enough I could pretty much figure that the fuel pump wasn't working. So since we were in a hurry to get this back on the road I got a fuel pump overnight and installed it.
It worked for about 25 ft! So now I could easily see that I have an intermittent electrical problem that effects the fuel pump. So what's left? The sending unit! What is a sending unit? Well it sound complicated, mysterious, sounds like a relay or something right? Well it's the plastic cap that fits to the top of the fuel tank and also encases the connectors for the fuel leads (plugs) and also includes the fuel level sensor/sender. They call the thing that floats on the fuel and monitors the level: a sender. So I guess they call the whole fuel tank cap a sending unit. Sounds good. OK I just had to get that out of the way for people that might not know exactly what it is. They surely don't give you a good explanation anywhere!
Here is a look at this commonly defective part!
Of course this unit is brand new in the box. I'll be going over the process of removing it and replacing it if you have the patience to scroll down.