Maybe stating something already mentioned... But have you replaced your fuel filter? I don't know if that would help... or if could be clogged. Not entirely sure how the system works but imagine a clogged filter could really put a wrench in things. My pump at 255,000 miles was still perfect. I replaced it at preventative maintenance.
I have now pulled my tank twice. It may seem daunting, though it's not that bad and a pump isn't that pricey off rock auto. I understand you'd rather not pull the tank but just in case you change your mind, here's how it works...
If I was near you I'd be happy to lend a hand.
Run truck till tank is as close to empty as practical. This job is actually a BREEZE if you do that, but a Royal nightmare if you don't. Don't ask me how I know...
Raise Truck: I got 4 ramps... put them opposite directions (so truck couldn't easily roll off). Then placed truck on them (with a jack).
Bleed Fuel Pressure: Pull fuel pump fuse, start truck till dies... or in your case just crank truck.
VENT AREA: Open ALL Garage doors and maybe even put a fan there.
Fuel Lines: you have two fuel lines (possibly one if newer returnless setup), these use a Quick disconnect tool. You can buy one at local parts store if you don't have one. It slides over the line and into the coupler, then the lines pop right apart. I put a rag below them just to make sure any residual fuel doesn't get in my face. The fuel lines are front of tank, near frame rail. metal goes to plastic (tank side).
Evap canister: this is second hardest part of job. Sometimes the quick disconnect fittings get old and fussy. You can douse them in WD40 or PB blaster... let set before you do project... then whipe off. Hopefully that loosens up the old dry plastic. The concept is to pinch the female end, and it releases the clip on the line going into it. Be patient, this part may literally take an hour. Some people reach up on the side of the tank and pop off the LARGER vent hose. You can do that or disconnect it at the vent AND canister. That one's not as bad, it's larger... but the purge line to tank is a PITA (small one going towards tank). I think you have the pancake style canister which should make it a tad easier.
Now the res of the job is a BREEZE.
Fill spout: the hose going from fill line and it's vent are two ring clamps rear of tank. Using an extension on a socket they come right off.
FYI ~ so long as tank is mostly empty... say only a gallon or so in there, it's pretty light.
Connectors... support tank with something underneath. I used my jack so I could adjust the height. Remove rear strap holding tank. It's one bolt and comes right off. Loosen front strap but don't remove it. Slowly lower tank down with jack... This should reveal the two connectors on the pump at top center of tank. One will have a locking clip. You must pull out the clip. This is a bit of a bear, but more than doable... You depress the locking tabs on the connectors and they come off. The other just has a tab you have to release. NOTE you can get the tank low enough so you can access these connectors without being under vehicle fishing with hands in dark. I reached under frame rail by rear passenger (driver side) and could get it.
Remove tank I laid under my tank for this, but you can also just let it drop.. onto a cloth of something under it. Remove that front strap and it will come right now.
Sounds like a lot... honestly, would be a couple hour job or less with a shop jack... but not too bad if you get it up on the ramps front and back. Biggest thing is making sure tank is EMPTY and fighting the evap connectors. Without that heck I could probably do it in 30 minutes. Layout is AWESOME from a maintenance and rebuild standpoint. I've dropped quite a few tanks and this is by FAR the easiest.
EXTRA CREDIT: you can clean the tank when it's out. I blew mine off really good before removing the pump to keep debris on top from getting inside. Then I emptied remaining gas into a gas can. LET THE TANK AIR OUT FOR A NIGHT OR TWO IF YOU HAVE TIME. From there I cleaned the tank. I put a little dawn dish soap into it, some water.... Wiped what I could with my arm and a rag... Then I just rinsed the living heck out of it till bubbles went away. If you do this let it air out REALLY well. I don't think a little water will hurt anything (lots of fuels have some water in them) but I didn't want it in there either.
Assembly is reverse of installation. Last tip, there's little orings in the Quick Connects for the evap system. Hit those with some PB blaster and it should come apart easier next time. I actually replaced those couplers all together. But was a PITA to do. Had to heat the line with heat gun, and pull couplers out. Melted one line so had to get another at junkyard.
