I have a 1982 Dodge D150 5.2L and it was parked two years ago and when parked it ran fine. I changed oil, oil filter and spark plugs. I put some fresh gas in it and was able to get it running and while running I bumped the bowl vent arm and it shut off immediately. Since then have been chasing my tail to get to run. I have changed out the fuel filter, fuel pump and cleaned out the fuel bowls in the carb as all of these had two year old gas in them. When cold truck will start as long as you give it some gas. From there it will run as long as you keep foot on gas to idle at higher rpm but as soon as I slowly back off and get to lower rpm it peters out. Seems like once it warms up and in try to let it idle and it cuts off it does not want to start again. Someone told me to check the egr valve so I took it off and made sure the diaphragm worked and it does move when you put a little bit of force on it. First time ever dealing with a carburetor, never dealt with anything this old before. If you have any ideas they would be greatly appreciated, I have to get running today so I can go to work tomorrow. Thanks.

 

You need to rebuild the carb first.

 

did you ever figure your problem out I have a 1979 ram charger aw100 that is doing the exact same thing