Wont start cranks good, acts like no fuel. ran great this morning to work but wouldnt start at quiting time

fuel pump inside gas tank is defective.

I would check and be sure I had fire to the plugs and fuel to the throttle body. I read what you wrote about the fuel pump but then on the end of the description where you put gas in the van the pump might not be working. If so you could have a bad wire to the fuel pump or a plugged fuel filter. Once you verify those items I would pull the 02 sensor ahead of the catalytic converter in the exhaust and make sure the cat or muffler is not plugged. If they are it will put back pressure on the engine and not allow fuel into the cyl. to fire.

Sounds like air in the system.

usually if thats the only way it will start that means you have no fuel to engine. first off, check the fuse and relay for the fuel pump. next get under car at fuel tank and put your hand on tank while someone turns ignition to on. if the pump works. then you can feel it vibrate. a fuel pump only turns on a few seconds, to pressurize the fuel line. then when running its on all the time. check fuse and relay first before doing anything else. have a good one !!

TRY FUEL FILTER IF U HAVENT YET

did you reset the alarm/immobiliser system every time the power was disconnected???

Try tapping on your PCM behind your glove box,also are you getting fuel pressure and a good blue spark at the plugs when cranking the engine?

There is a control module on inner fender well under hood,natorious for causing this type problem,ussualy on drivers side.

bad ecm relay replace relay or swap relays in the ipdm

well the 4 things needed are air fuel compression and ignition make sure there is good healthy blue spark strong fuel pressure and a clean air filter if thats all good then check the compression