My '01 Ram 1500 has it...bad. In fact, it's more like 1/2 tank syndrome these days. Kinda tired of using the odometer to gauge how much fuel I have, but that happens to be more accurate than my gas gauge. Does anyone know the cause, or more importantly, the fix???

Those trucks like to eat up sending units. Was a real problem back in 1997-2002. All the new units should be ok....just a PIA to have to drop the tank.
Of course, you could lift the box up 18" and change it...

Lifting the bed can be if all thwarting bolts come our good and you have a couple friends to help remove or a way to lift it straight up

I've had so much greif changing out aftermarket fuel pumps for those trucks and then finding that the guage is a POS Nothing like doing the same job 2 or 3 times for free...

I'd really recommend using the Mopar one....

I pulled out a gas station one night, reading over a 1/4 tank and I ran out of fuel... definitely is a pain, but not I hit a half tank and I fill up. Tank is 34 gallons and at a 1/2 it took 19 gallons. Hard to believe the next 1/4 is 15 gallons.

We used to get the odd one from NAPA etc.....nothing but grief. We just made it a house policy to use the OEM stuff.....NO problems...you're probably looking at 100 bucks or so.

OK, I guess I have until 26 Oct (opening day of archery season ) to get this done. While doing some on-line shopping, all I see is the entire fuel pump assembly. However, the youtube tutorial I watched was a guy replacing just the sending unit portion attached to the side of the fuel pump assembly. I guess that since getting to the unit is such a chore, swapping the entire unit makes lots of sense. Thanks a bunch for all the help!

My 01 Diesel left me stranded once due to this. Back in the old days the rheostat portion of the sending unit used to be real wire wound around a phenolic material - nowadays its more like a printed circuit board. Oh, and by the way, my OE sending unit, just like my lift pump, is a CARTER part - CARTER is stamped right on the rheostat part of the sending unit. I've bought lots of aftermarket parts from Airtex, Standard ignition, etc. that turned out to be the OE manufacturer. You might be able to use an aftermarket part and find it's really a re-boxed OE part. AN example - I just replaced the master and slave cylinder in my 01 and the replacement parts are the exact same manufacturer as the OE one the factory installed. Replaced the neutral safety switch in my 6 speed with one sold by Airtex - get it out of the box, and stamped into the plastic part of the housing is 'POLLACK' - same as the OE one installed in 2000. So I'd check online, like at Rock Auto, and look at the pics, before shelling out big $$ for a dealer part.

Dealers typically just lift the bed to do this. 8 bolts that usually zip right out with an impact, even if rusty. Then unhook the tail light harness, and remove spare tire winch rod. Bed can be up off the frame in under 30 minutes and beats trying to drain the tank or fighting trying to lower it when full

Just get the sending unit....the OEM one....or if you don't care about the 300.00 plus for a pump assy........

Well, nearly two years later I still hadn't gotten around to replacing the sending unit. My fuel pump left me stranded the other day, so I reckon that was the motivation I needed. Two things: I had roughly 2/3 of a tank. I didn't want to drop the tank with that much gas, so I did the bed lift method. Although getting the 6 bolts out was tough (due to factory loc tite), that's the only way I'd ever do it again. Take 4 bolts out completely, and leave the 2 rearward most bolts about half way out. Prop up the front of the bed and get to work. Way easier than I imagined... Also, there were no Mopar fuel pumps in the vicinity, so I went with an Aeromotive pump from Autozone. Once installed, I filled the tank and reset to trip meter. When I get around 250 miles on the tank I'll throw a 5 gallon can of gas in the bed and run it down to nothing (or close to it if it seems to be working correctly). I'll report back if I have any issues with the Aeromotive pump. Thanks to all for the help above.