I don't think there is an actual filter in the accumulator by 88. My truck is a mid-year 87 and it's original casing did not come apart. It only had the screen inside, no real filter.
My bad.
On a 25-yr old truck, where there were some changeups in close model years, mutations can definately occur (parts availability, home mechanics, etc)
Deep casing/won't come apart = accumulator (later 87s and 88s?)
Shallower casing/comes apart w/ O-ring seal = replaceable paper cartridge filter (1986, some 1987s?)
If there is a cartridge filter, it is fairly easy to replace roadside, after the first time when you remove one of the guard bolts so it can be swung aside.
All three years, as far as I know, have the high-pressure in-line filter downstream from the rail pump, under the very front of the cab, just before the fuel line curves upward. It can be a b**** to replace, specially on a 2wd - I usually have to get some blocks under the driver's wheel to get under there to get at it, usually get gas down my arm, in my face etc. If there is significant dirt in the line (eg: rusty fuel tank), this filter can clog up amazingly fast, even if there is a cartridge filter acting as a prefilter. This will result in a Jeckyll-Hyde pattern of start up - runs fine; drive it for a bit - will start sputtering and choking, lose power. Will sorta limp if you feather the gas pedal, dies if you tromp it! Pull it over, let it sit (not running) for a bit, it may come back and run fine to limp home, or it may sputter and lose power right away!
Anyway, enough of my sputtering! Like adsm says, check the fuel pressure (or if you don't have a gage, carefully poke the fuel Schrader fitting with a Phillips - have a rag handy to catch fuel spray, don't spary yourself in the face, and dont do this on a hot engine) Low rail pressure could indicate a bad rail pump, or a starved pump (bad lift pump or other problems on the supply side - unlikely given you have replaced the in-tank pump and fuel line) or a clogged in-line filter ( if the pressure gets better AFTER the truck has run then sat awhile, or the Schrader squirts Koolaid-colored gas, suspect the filter!)
One other thought - is your truck a single or dual tank. On dual tank trucks, the switchover valve is known to go bad and cause problems. If this is the case, you could check the valve by bypassing the valve on the supply line (PO on my 88 had done this by using an inline filter as a splice!) and see if that helps.
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