Changed out fuel filter because engine did not seem to get gas or start enless i put a gas soaked rag in the air cleaner...start for a couple on seconds then die...fuel pump seems to be working there is gas going to both sides of new filter...what else could it be.even unhooked the battery to reset computer....Please help Thanks John

As it cranks, is there white or black exhaust smoke ?? If yes, the fuel injectors have solid build up on the tips. Normally, a quart bottle of injector cleaner treats 20 gallons. Pour 5 to 7 quarts of fuel injector cleaner. With cold engine (been parked for at least an hour or overnight), while cranking engine, have 2nd person spray starting fluid into air filter. DO NOT PRESS ON GAS PEDAL !!! Let the starting fluid do its job of starting the car. Starting fluid is highly combustible, so its important you don't give any gas while its cranking and 2nd person is spraying into air filter. When engine starts, stop spraying starting fluid and give a little gas. If engine begins to die, immediately spray a little starting fluid again. When engine begins to run, let it run a few minutes to let fuel injector cleaner to do its job (loosen solid carbon build up on tips of fuel injectors).

worn fuel pump / low fuel pressure / engine management fault ?

Check compression test minimum 125 psi and above with gas pedal down check fuel pressure and ignition timing, check idle speed valve PCV valve is on top of your rocket cover with a hose going to inlet manifold by hose vacuum hose leaking or loose .air filter ,or exhaust blockage .

I got this from Haynes Diesel Engine Repair Manual. I bought it for my 6.2.
1. Remove the fuel filler cap and air cleaner assembly.
2. On filters without an air bleed screw, place a rag under the filter to soak up fuel and detach the lower clip FIRST to release pressure and then the top clip. They pop off with a screwdriver.
3. On filters with an air bleed screw (top passenger side) drain fuel from the filter by opening the screw first and the engine water drain valve (engine front near thermostat) if it has one. Detach the clips and remove filter.
4.Make sure the seating surface is clean and place new filter in position. On non-air bleed filters put the upper clip on FIRST. On air bleed filters secure both clips, then close the valve and attach a piece of hose to the bleed port into a pail.
5. Air must be purged BEFORE start up, so disconnect the pink wire from the top of the injector pump and crank the engine in 10 second cycles with a 30 second wait time until clear bubble-free fuel comes out the lower fitting or air bleed. Connect the lower clip on the non-air bleed , close the bleed hose and reconnect the pink wire.
6. Start the engine and let it idle for several minutes to purge any remaining air and check for leaks.
Hope this helps.

How long has it been since the spark plugs were changed? Sounds like a good tuneup is in order. New spark plugs(try the new E3 plugs, expensive, but worthit), Air filter, fuel filter, injector cleaner in gas tank.

Issue with Gaz Line transportation.. Check input Gas Line... Take Off Gaz line from Carb Start engine see if gas came out if yes..Check your intake carb for Durt inside the line ...Also chek all your Vaccum Line and sensor Volvo are sensitive for Vaccum lost and The Carb need it ..Also if it Fuel injection... Check for Ignition Control Box for Malfunctioning Relay ...good luck

Could be FICM.....normally 48V...if voltage drops to low it will not start....I had one that was intermittent and then gave up ghost. Do you have a scangauge? Good tool to monitor engine parameters real time

i would try a compression test on all cyls and compare readings, sounds like something internal

try cleaning the throttle body,a build up of carbon collects behind the blade and restricts the air flow..sometimes too much for the computer to compensate for,just stop at yur locale parts store and get some cleaner and spray some on a rag,while holding the throttle open with the engine off,clean it with the rag soaked in cleaner,then take it for a ride around the block so the computer can relearn the settings for the air bypass solenoid

Air cleaner is clean right ? try shooting a little fuel in the throat of the throttle body or air cleaner to see if it starts .. if so you have a fuel problem .. fuel filter or fuel pump needs changed thanks jerry holler if you need more .