2001 chevy van HELP PLEASE

I was going down the freway and started to lose power the engine started to bog down.. I made it to a parst store and did a code search it came up multiple missfires so I changed the plugs,wires,vgr valve,distribiture cap,rotor, and still have the same problem then I changed the crank postition sensor...still no help...Then I changed the fule filter and checked pressure and it was fine... I remved two o2 sensors and it finally ran good but loud. i replace them and now back to the same problem bogging down no power....PLEASE CAN SOMEONE HELP ME

What engine?
How many miles on it?
Got full fuel pump pressure?
What was the fuel pressure reading?
What is engine vacuum at idle and at 2K rpm?

What engine?
How many miles on it?
Got full fuel pump pressure?
What was the fuel pressure reading?
What is engine vacuum at idle and at 2K rpm?

had it at a shop yesterday they changed the fuel filter and checked pressure said was fine
it si a 350 5.7 with air 2001 chev express 2500
80k miles
idk the vacume

Did they go threw the full fuel pressure test or just throw a gauge on it and say it was good.
What pressure reading did they get?
What is the engine vacuum readings.

The expres van has a fuel pump wiring problem at transmissin cross member.

Get a fuel pressure gauge on it and tape to out side of windshield or outside mirrow.
Drive it for a hr or 2 or untill it acts up and post back your fuel pressure reading when it is acting up.
Also watch voltage on the 12 volt fuel pump wire to pump and ground.
The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

I do not have the tools to check the pressure but I can say the minute I throw it in drive and hit the gas it bogs down but if the 02 sensors are pulled it runs fine. and I changed the o2 sensor also

Rent borrow or buy a fuel pressure gauge.
Some auto parts places have a loaner tool program.
We need fuel pressure readings and vacuum readings to be able to help you.
Good luck.

funny thing i drilled a 1/4" hole in the cadalic converter and started it banged on the converter and then put a bolt back in it and it is running fine now go figure!