289 hesitating, sputtering, and backfiring.

The first of many posts.
Yes there are similar post on here but none really like mine that I could find. I can guesstimate but my mechanic skill are almost equal to a 5 year old.  Actually I could probably learn a thing or two from him/her.

I have a 1965 289 that has developed a issue. It idles, starts and runs fine but as soon as the cars been driven for 30 minutes it sputters and hesitates. This is day 3 of this issue. I can rev the heck out of it to make it run but down shifting or shifting to a higher gear makes it sputter again. If i stay at a consistent speed its ok. Recently I replaced the plugs, Coil, condensor and points it ran fine for 2 maybe 3 weeks an this started to happen. I've checked sparkplug wires and other wires in the engine compartment an they all look fine.  None of them are melted or frayed.

Some other symptoms that could possible help you to help me is.  I turned the key off and it still ran and died.  This only happen twice.  Another symptom is I hear a sucking comming from my Carburator when I pulled off my air filter?

Alos this has been my daily driver for a month and half and for what ever reason this started.  An my comuttee is about 30-40 minutes highway an stop an go at lights.

Also I know I need to switch from points to electric its all in time an money.  Right now I just want to get to work.  Thanks for you help I appreciate it.  

You may have an air/fuel delivery issue....like too much or not enough. When the car is cold and needs a richer mixture the extra fuel is used and burned off. As soon as the engine warms up (after your 30 minutes) it needs a leaner mixture and the extra can cause some black smoke out of the tail pipe and can create carbon in the combustion chambers which will glow when hot and act like spark plugs to keep the engine running even when the ignition is turned off. At idle a too rich motor will run rough and sputter/ die. At a constant speed you are burning off the excess and when revved up you are doing the same thing...burning off the excess. At idle it just doesn't work.
Pull a spark plug and see if it is sooty black. If so, you are getting too much fuel. Check your tail pipe. If it is sooty black inside or smokes a little then you are too rich in fuel mixture. If it looks normal then you may have a vacuum leak in the gasket between the carb and intake manifold. It is normal to hear a little suction sound coming from the carb at idle since air is sucked into the motor. Too much sound could indicate a vacuum leak. The effect of a vacuum leak would have similar symptoms to what was mentioned above. When cold the rich mixture from the choke will tend to hide the effects of the vac leak until the engine warms up and the choke comes off. Then the vaccum leak will cause a too lean situation at idle and cause the motor to idle rough, backfire and die too.
At cruising speed and when revved up a vac leak is dimished by the larger volume of air required by the engine at speed. At idle it is just too much for the motor after it warmed up. The spark plugs will be dry and light to white colored when a too lean condition exists from a vacuum leak.

1) Check to be sure your choke is opening all the way when warmed up. Gotta be straight up and down or you will have the problems you are having.

2) Tap (not too hard) the top of the carb where the fuel line goes in 5 or 6 times with the plastic end of a screw driver. Sometimes a little crud gets past the fuel filter (maybe replace it?) and lodges between the needle and seat under the carb float and keeps it slightly open rather than closing all the way & shutting off the extra fuel.

3) Unbolt your carb from the motor and put a new carb to manifold gasket in under the carb and carb spacer to ditch the most likely place for a vacuum leak. If it still runs bad after checking or replacing the vacuum line(s) to the distributor from the carb (and tranny if its an auto trans). An old or cracked hose will cause a vac leak too. You just worked on the ignition system and may have broken or cracked an old vac hose in the process with knowing it.
 
4) Worst case is you might have a vacuum leak in a manifold to cylinder head gasket.
Spray carb cleaner along the mating surface of the cylinder head and intake manifold on top of the motor slowly on both sides while it is idling. If the motor speeds up then you have found the source of the manifold vacuum leak.  

If the above four things don't work take the top off your carb & check to see if your carb float level and inlet needle valve are OK and be sure your power valve didn't rupture and is leaking excess fuel into the motor. If you have the stock Ford Autolite two or four barrel carb they are super easy to work on.
Just go to an auto parts store and buy the cheap rebuild kit that comes with a guage for measuring your float level and also contains a diagram/instructions showing you how to easily replace the power valve. That is probably all you need to do - especially if you don't want to tackle the rest of a complete carb rebuild given your stated level of expertise.

Come back on line and say what you find and then we'll go from there to solve the problem.  

Firstly welcome to the forum.  Before you do any else but verify that the choke is opening when hot, replace the fuel filter attached to the front of the carb. or if you have the fuel pump mounted one take the can off and make sure the filter element is not plugged up.  from here you can go into what JBirch has stated.jlg  

One thing I've run into is fuel contamination.  Fuel filter allows passage cold/first started - then, it only gets worse with mileage.  Jbirch and jlg2002 are right on target.  Sounds like fuel starvation or perhaps too much fuel with a sticking float.  Doesn't sound like ignition at all.  

Appreciate all the advice.  It was a couple diffrent things.  I brought it to a friend to bring everything into line again.  A lot of it was just stuff out of whack just enough to make it sound like a popcorn machine. One issues was the points.  I didnt have the little felt thing that keeps it lubricated.  Another was my timming was off.  An lastly for some reason my electronic choke was getting hot and sticking open.  

Replace those points with a Pertronix Ignitor, very easy install and never have that sort of issue again.  

Pertronix does wonders for a car... it is one of the best things I ever did for my car!
The stock carb settings on the 2bl autolite 2100 needles are between 2 and 2 1/2 turns on EACH needle out from closed... that always gets you well within the ballpark and get it running fine, assuming that like jlg2002 said your choke is fully opening. A symptom of a un-opening choke is absolutly aweful gas milage. My guess with jbirch. That your mixture isn't quite right..