75 ford
started with 2 Barrel Carb
Upgraded to a 4 Barrel Edlebrock on holley 600

The truck ran fine for the previous weeks.

One night it stumbled going up hill, and it started from there.

Its started fine and runs for 30seconds, and then it stumbles to a idle and dies.
I replaced the Ignition Coil Module, Ignition Coil, ignition cap inside distributor.

The last time i looked at the plugs they looked quite decent without fouling.

Im stumped on why this thing is not running properly.
The next thing i will do is replace the spark plug and set my timing so it doesn't run as rich.

 

So it idles for a while and then stumbles and dies? Mine did that for a while, only would die if idling, was fine at even 100rpm above idle. Problem was gone when I filled the tank with fresh gas.

 

The truck will not stay at idle.. Tonight I moved it and I could hear the vacuum when I pressed the brakes, but I also didnt allow it to warm up fully

 

If you're driving down the road, will it eventually die, or will it stay running? If it begins to die at idle, can you pump the gas and revive it before it dies?

 

 

It's dies before I can pull away. I can pump the accelerator to keep it running, but once I take my foot off it will die within 10 seconds.

 

Okay, that is different than what mine did. Mine would last about a minute before dying.

How is your fuel pump?

 

 

The fuel pump is in good condition.. It will fill the carb and spray fuel.

 

Sounds like its running rich. Check the mixture recently?

 

Is this different than adjusting the timing?
The carb I have was jetted to run a modded 360, but this problem hasn't happened before to warrant changing the jets?

 

Carbs have idle screws as well as jets to adjust the mixture. Not sure what the adjustment procedure is with a Holley though. The idle screws may have backed out, causing your mixture to be really rich.

 

On my Holley, there was two idle mixture screws, one on each side of the bowl. They are very small flat head screws. If I remember, you would turn them all the way in and then back them out 1 and 1/2 turns. This would usually be good enough to run. Then I believe you Turn them out or in together in 1/2 turn increments to achieve the best idle. You might have to adjust your idle speed screw as your idle speed may have changed after that.

 

This doesn't have anything to do with how rich or lean it runs. That is a function of carb adjustment.

 

I would re-check all the coil wiring. In the third picture from the top, you have two wires on the coil half-azzed twisted together. Could be a problem of the coil not getting consistent voltage.

Then go on and troubleshoot from there