Fuel Injection Problem? Help Please

I have 1996 Dodge Ram v6 5.2l with 165,010 miles.

Recently I was leaving police academy and I noticed when I started my truck and left, my exaust was making a weird sound.. ( like a muffled sound.. hard to explain on here lol) Shortly down the road my check engine light came on flashing (misfire codes). I know this is a misfire code because this happened like 5 months ago too. Anyways after the check engine light came on the truck stalled on me and it took like 2 minutes to get it started up again. Also when im driving and when I hit 45mph the engine starts to shake it seems like

Let me just say what work has been done on it before I tell you what the dodge dealership told me the problem was.

I changed the spark plugs, spark plug wires, distributor cap, coil.

My first misfire problems turned out to be fuel injector was bad so they replaced it and also cleaned out the carbon build up.

Now let me tell you about what dodge told me the problems was.

1. Spark plugs fouled
2. Distributor, wires, coil
3 .Intake gasket leaking

After getting this info I went home with my truck barely lol. I decided to test my spark plug and wires. I did this by pulling one plug at time and hooking it back to the wire and laying it on something metal and all of them fired up. Now I know everything should be good with my wires,cap,plugs.

Am I looking at injection problem again? If so how could I test the injector to see if they;re bad?
Below is the picture of my problems lol

If the repair is going to cost alot.. I thinking about just selling the truck so if anyone is interested.. just let me know