At just key on I believe fuel pressure was 55-56 I would just key on then turn key off after 10 seconds ( for key on test only)

 

I'm having similar issues, although probably different causes.

But just to through it out there, check your PVC hose connection. I had a hell of a time trying to keep this thing steady at 100km as it was bucking, and only cruise control would keep throttle up at that speed. It was running pretty rough on idle and I thought it could stall on me (but never did). Then I discovered only today that the PVC hose wasn't even connected to the intake manifold lol.

Other things you can try are: taking off the EGR valve and cleaning it, replacing gasket and re-installing (this affects exhaust and causes misfires if not running right). You can also clean out your MAF sensor, which would cause problems if the screen is clogged with dirt and choking your air flow.

I checked both of those today on mine and they were okay. Up next is checking the gears in the distributor to see how that's holding up.

 

And what's the pressure 10 minutes after you turn the key off?

 

I didn't wait that long
Say it is what you are you saying what do I need to replace

 

Really, there are only two things that can cause lean mixture to the point of misfires. Vacuum leaks (big ones, if it's misfiring) and poor fuel flow (clogged filter, pinched lines, excessive leakage back into the tank, either at the regulator or in the tank near the pump).

Until you figure out which problem you have, "throwing parts at it" isn't wise. That's the most expensive way to solve the problem.

Diagnosing what exactly is wrong is the first step.

Pressure on prime (key on for a few seconds) should be 60-66 PSI (assuming you have a W in the 8th position of the VIN, and it hasn't been updated to the later multiport-flexible injection system). After 10 minutes, it should still be over 50 PSI. If it falls too quickly, you have leakage somewhere.

You should also check the pump output pressure. That's checked at the fuel filter. I usually disconnect the line going into the fuel filter and use one of the adapters in the pressure tester kit to attach that line from the fuel pump directly to the gauge. You can also disconnect the outlet line and use an adapter to attach the gauge to the filter outlet fitting. The gauge is the end of the line for this test, the line to the engine is disconnected. The pump should put out at least ~ 72 PSI, and could be as high as 10x (108??, I'm not sure). Again, leave the gauge attached after the pump shuts off. It should maintain 60PSI+ for 10 minutes. If it doesn't, there's a leak in the tank, or a bad pump.

All my numbers are from (possibly faulty) memory. There's a sticky on the 2nd gen tech forum here about fuel pressure and leakdown testing. If I'm off from those numbers, go with what's in that thread.

If you post all four readings, at the service port at prime, 10 minutes later, and at the fuel filter at prime and 10 minutes later, we'll be closer to diagnosing the actual problem.

Also, check for vacuum leaks. Thanks for mentioning that @Vovin. Either the PCV vacuum line or the brake booster line could cause excess unmetered air in the manifold, leading to lean mixture and misfires.

 

Want acceletate pass 30 but if I disconnect master airflow sensor I can accelerate a little bit better about 55

 

Well finally me and my dad cleaned the injectors everything seems to be normal again turns right on and I can accelerate took it for a couple test drives and it worked good I guess tomorrow on the way to work and back home will be the real tests

 

Just for the record ran good for a day and a half after cleaning injectors then the problem returned I had good fuel pressure no vac leak well we decided to disconnect fuel line at fuel filter connect a hose and open fuse box remove relay for fuel pump and put a single jumper wire to activate pump therefore siphoning the gas out got about 8 gallons out Well while the fuel pump was on we could tell it was the culprit because we could here it pulsing it sounded like a phone vibrating and the flow was not steady it would be a decent flow then slow down a decent flow then slow down I swapped fuel pump via warranty at oreileys and voila problem solved no bogging down no loss of power my blazer is alive again