Slight missfire problem

Anyways, I have a 1979 F-150 with a 351w. It has a Mild cam, Headers, edelbrock 600cfm, Only mods i know of. Anyways, everysince I bought this truck about 4 months ago, its had a "slight" missfire to it especially when I hardly give it any throttle or Low rpm. I also Have to run about 1/4 choke for it to run smooth. I have replaced plugs, plug wires, distrubter cap and rotor, coil pack, inline fuel filter, and have used carb cleaner on my carb. Nothing really helped it at all.
Well, one day after I did all this, I decided that I would pull the distrubter and check and see if the gears were damaged. They all were ok. So I tried to get the distrubter back in where I took it out, and couldn't so I put it 1 tooth off, can't remember which way. And the missfire was completely gone, and I could run it with "No choke", instead of running with half.
It ran Good for about 2 weeks, then about a week ago, I decided to be a show off and do a burnout to show my dads dodge up :S . Long story short, it fell flat on its face, and now the slight missfire is back. And I have to run with 1/4 choke for it to run halfway smooth again.
I'm not sure what this could be, carb? Ignition problem? Any help will be appreciated.
What are your idle misxture screws set to? 2 1/2 turns "out" is a good place to start and then fine tune with a vacuum gauge.
Josh

Anyways, I have a 1979 F-150 with a 351w. It has a Mild cam, Headers, edelbrock 600cfm, Only mods i know of. Anyways, everysince I bought this truck about 4 months ago, its had a "slight" missfire to it especially when I hardly give it any throttle or Low rpm. I also Have to run about 1/4 choke for it to run smooth. I have replaced plugs, plug wires, distrubter cap and rotor, coil pack, inline fuel filter, and have used carb cleaner on my carb. Nothing really helped it at all.
Well, one day after I did all this, I decided that I would pull the distrubter and check and see if the gears were damaged. They all were ok. So I tried to get the distrubter back in where I took it out, and couldn't so I put it 1 tooth off, can't remember which way. And the missfire was completely gone, and I could run it with "No choke", instead of running with half.
It ran Good for about 2 weeks, then about a week ago, I decided to be a show off and do a burnout to show my dads dodge up :S . Long story short, it fell flat on its face, and now the slight missfire is back. And I have to run with 1/4 choke for it to run halfway smooth again.
I'm not sure what this could be, carb? Ignition problem? Any help will be appreciated.
Hello my name is Gary.
it seems like it has a timing problem cause you said when u removed the distributor on tooth and you said it ran good. so i would try the time and chain and gear cause it sounds like it wore, thats why it jumps and thats why it runs good and then it wont run good. and that might be the problem so check that!
thanks have a great day







