96 Blazer running rough

I have a 96 Blazer vortec 4X4 vin. w. It idles horrible jumping from 600 to 800 R.P.M when i accelerate it has hardly any power and spits and sputters.

I have replaced
-fuel pump
-all filters
-did complete tune up with ac-delco parts
-ignition coil
-ignition control module
-cleaned MAF Sensor
-cleaned throttle body
-converted CPI injection to MFI

And the the blazer is still doing the same old things any advice would be greatly appreciated, thanks.

What is the fuel pressure?
Any codes or check engine lights?
Good hot blue spark to all plugs?

fuel pressure is at 65psi no codes and good spark, and i appreciate your time and help

A good engine capable scanner may point you to the problem.
But first.
We need readings from a full fuel pressure check.
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 pressures.
Cold start should be 64-65 lbs of pressure.
The 95 or yours is 55/61 lbs 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 55/61 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post-back fuel pressure readings.

Remember a fuel pump pressure regulator controls the pressure and maintains a steady pressure depending on engine load and vacuum.
It has to be capable of producing higher pressure than the regulated pressure.

The fuel pressure controls pressure and can leak off or bypass pressure

Thanks for your help, last night i decided to pull the plugs and wires and inspect the plugs and test the wires and the real hard plug to get out number five i believe had some broken porcelion so i changed it today and it rins like a top.

You welcome and thanks for posting back what you found and how it went.
Good luck
MT