79 mid-throttle "chugging" issue

[Deus Ex Verra]

I have a 79 1 ton G40 Series van.

On my way home tonight the van was running fine and smooth like always until I came to a red light and slowed to a stop. There was no odd noise, or any strange behaviour until full idle and I noticed the van seemed to almost die, as if it were struggling to stay running. I gave it some gas and it helped, but it still idled wierd. When the light turned green it ran fine until I gave it about mid throttle gas and it seemed as if the fuel had suddenly been blocked from entering the engine, as if it instantly died - as if a valve or tube had suddenly been blocked- but would fire a few more times and do it again. I'm not a car expert so i could be totally off but I'm guessing its the carb. Any ideas on what it is and how to fix it?

It did it all the way home, I even stopped at a friends house to try turning it off and starting it again to no avail. It runs perfectly fine in neutral, no issues resembling this whatsoever. Only happens in gear (including reverse)

thanks

[Deus Ex Verra]

turned out to be a faulty spark plug wire.