If you get it driving it will run fine when u are giving it gas, but when u let the idle fall it just stalls ... any idea?
This is extremely common. It’s actually quite normal for an AMC Eagle. The very first thing I suspect is the acceleration pump adjustment. It’s a single set screw underneath the cover plate on the top of the carb, the one that can be removed while the car is running. A rod running through the side of the carb goes through the center of a pipe, and this set screw adjusts the relation of the pipe around the rod. I consider that set screw the golden ticket to making the Carter carb run well.
In each and every one of my 258 automatic Eagles I've had the same problem arise where the car would run perfectly fine at idle and it would accelerate perfectly fine once the pedal was pushed, but the car would stall as soon as you touched the pedal. Specifically it would stall anytime I pushed the pedal slowly. I learned to push the brake with my left foot and give several quick thrusts on the gas pedal with my right foot to get the car past the trouble spot.
The worst time was when I would take my foot of the gas while entering a curve and then in the middle of the curve I would slowly start to push the pedal down to start speeding up through the end of the curve. I’d forget to double foot or to thrust the pedal, and it would stall out. Dozens of times I’ve been in the middle of a curve without power-steering using both hands to remain in control. [This is the biggest reason I’ve always ditched the neutral safety switch in every automatic Eagle I own. In a stalled Eagle going around a curve you don’t have both hands free to manipulate the gearshift lever in and out of neutral. On my Eagles I can reach right down and turn the key and the car will start while still in drive. I consider a neutral safety switch a threat to the safe operation of an Eagle because of how often this has happened to me].
One day I had an especially poor running Eagle sedan. The carb had been rebuilt multiple times and was in exceptional condition. I turned the idle mixture screws until the car was smoothly running very fast, approximately 2000 RPM. I slowly turned the throttle by hand as if slowly pushing the gas pedal. The Engine RPMs instantly decreased to approximately 500 RPM and then slowly climbed from there at a nice steady rate all the way back up and past 2000 RPM. To some degree I’ve initially seen the same “dip” in RPM in every Eagle I’ve owned. I learned to adjust that accelerator pump set screw until there was no “dip” in RPM as the pedal was slowly pushed in. After learning that single adjustment I have taken several terribly running Eagles and made them purr. It is the number one reason I get such good gas mileage from my stock Eagles.