Misfire? Now with video

So I just got my 89 b2200. It starts right up, I think it takes less cranks than my fuel injected vehicles I just noticed tonight that I think it has a small misfire. I started it and drove it around the block and parked it in the driveway. While I was walking around like every 3 seconds I could hear a misfire from the exhaust. The pipe is rusted out before the muffler so it made it pretty easy to hear. It doesnt make the truck shake, there is no smoke, the truck runs fine. I actually ended up getting back in it and driving around town for fun with no issues. The truck is stock. I threw some cleaner in the gas tank to see if that clears it up. Changing the air filter, fuel filter, pcv, and changing the oil tomorrow morning.

The previous owner said he raised the timing a little bit and said it made the idle go up. Which i can tell it idles a little higher than normal. So im going to try and check the timing tomorrow to. Any ideas on this slight miss? If you were sitting in the truck you would never know its actually missing. I mean it does run a tad ruff and not smooth like my fuel injected cars but nothing that I would ever consider alarming. Thanks for the help guys

yea probly just timing, or maybe a small vacuum leak, maybe your egr valve is clogged. that's one of the most common issues that I can think of. mine did that every once in a while, like a little poof from the exhaust, im not sure if it was running lean, or if it was the timing. jus play with it, turn the dizzy back and forth n stuff. u can spray some starter fluid around the carb and if theres any leaks it will suck the fluid in and you will here the rpms change.

So I did some little stuff to her today. I changed the fuel filter (Previous owner had it installed backwards) Just to make sure im not the retard the arrow is the direction of flow correct. He had the arrow pointed back to the tank.

Changed the air filter, oil, pcv valve, and also sprayed some carb cleaner in the carb. It still has it high idle that I am guessing is from timing or tampering with the car. But she runs a lot better now. More smooth accel and feels like some more power.

I was spray the carb cleaner around and i think i might have a small vac leak around the carb or intake so i think ill buy a gasket kit off ebay and change both of those gaskets while I remove the useless vac hoses this thing has.

Lastly I did check the timing but could not read the marks very well so I just left it. But it looked as if the pointer on the balancer was pointing to the T on the cover. This I think is 0 timing advance correct?

yea if they line up right at tdc its 0 advance, however, he may have advanced the timing by moving the distributor. but if it fires right up like u say, Its probly pretty close.

Something to look for...
If your distributor cap doesn't have a vent, the air inside can become ionized, and the spark will actually jump around inside the cap. Most new caps have a vent, just to eliminate this phenomenon.

Ok just changed the plugs, wires, cap and rotor out and still the same thing. Check for vac leak again after having the air intake off (I think there was one undone). Still missing but I have video to show you. I also set the timeing to 6, and played with one of the screws on the carb all it did is make it worse so I put it back. I messed with the fuel mixture one I believe. I can find anything on how to get this carb running correct.

So ever figure out your mis?

89 b2200 stock everything.
Im having misfires now, when i take off from a start 1st is fine, 2nd i can feel it bogging down and missing, then it levels out and i shift, 3rd does the same and when im up to 55-60 its ok for a while, then it starts missing again as im cruising.

Ive changed plugs, wires, cap/rotor, air filter, fuel filter, oil/filter, pcv, a different EGR valve i got from the junkyard(had a check engine light saying EGR valve) checked the timing, did a new timing belt, checked for vacuum leaks.

If the EGR valve wasnt 200+$ id buy a new one, any ideas?

clean all the carbon out of the egr valve.