B2600 NOT RUNNING NEED HELP!!!!!

I have a B2600, I had timing issues but I got it all sorted out. It is now in perfect time according to the light, it is very hard to start in the morning, it's not even cold out, it turns over for a while and then fires a couple of times and it takes about 10 or more tries to get it to start?
Once it is started it idles rough until it worms up a little and then it idles just fine.
But when you push on the gas peddle very hard at all then it just sputters? If you lightly push on the gas it accelerates just fine, I can get it up to 65mph down the high way, but it takes me a few miles. Anyway, I drove it 3 miles to work, when I went to leave it wouldn't start? and I ended up pulling it home. The next morning I went out and it started right up, I let it idle for a couple minutes and then I shut it off. Again it would not start???. I have only had this little pickup for a month, when I got it 3 injectors were replaced along with some other stuff. I replaced the fuel filter and I checked the fuel pump and it works just fine. I also checked spark (when it wouldn't start) and it seemed just fine.
Here is a video of it running, I hope it helps.

If anyone has any ideas please let me know, this is just about my only vehicle and I need to get it going ASAP
THANKS for any help or info

Oh, when the engine is surging in the video, that's when the pedal is to the floor.
When the engine RPM goes up that's when I slowly push on the pedal.
THANKS

Have you checked your ecm? Passenger side kick panel is where it's hiding. Do a search on here about leaking capacitors with these ecm's. Lots of good info about that as it is a common issue with the fuel injected trucks.

Thanks, I'll give it a look.
What should I look for when I pull it out?
Thanks again

p341074 That thread will tell you just about anything you need to know about the ecm. Shows quite a few pics of which capacitors to look for.

Have you checked the fuel filter?

THANKS for your time and trouble, I'll get it pulled apart today.

Yes I replaced the fuel filter and the I also checked the fuel pump.
Thanks

Check and clean the connection at the mass air sensor. Also check your throttle position sensor.
Here is a link to the Mazda Workshop Manual.

Does it do this "full throttle thing" all the time? Only at cold start up? Only at warm start up?
Have you checked your spark plugs?

How did you check the pump? Did you check the fuel pump pressure with a gauge, or did you just pull a line off at the filter and verify that it would shoot a stream of gas 25 feet?

Without a pressure gauge, a lot of times, truck owners will use that latter method and consider a far shooting stream of gas an indication of proper fuel pressure. It's not. 15-20 PSI will do that. It will allow the truck to run but it will also give you the slow acceleration problems you are having as well as the hard starting... as will an ECM.

So I would inspect the ECM as mentioned above. I would then check the fuel pressure per the manual that SCL linked to above if you haven't already. There are a few things to test there. You could have a weak pump, clogged filter/sock in the tank, or a bad regulator. I have just talked to the second person in the last month that has had a rusted line on the pickup/sender unit INSIDE the tank. So it was and "internal leak" that was impossible to find without using a pressure gauge or pulling the sending unit.

As an easy and quick test, I would pull the vacuum line off the fuel pressure regulator and inspect for signs of fuel. If you find fuel, then it's bad. If not, it's doesn't mean it's good (you still need to do a fuel pressure test) to make sure it's regulating to the proper pressure.

Also, how did you determine that 3 injectors were bad? Had this truck been sitting for a while?

What other parts did you replace?