Dart wont stay running

[Sick_Six225]

I have a 72 Dodge Dart Swinger, 225ci, 2bbl, was running great two weeks ago now when I start it all it wants to do is sound like its fighting to stay running and then it just dies. Was thinking it could be air leak. I put it in drive and reverse and it then seemed as it was just fine but as soon as i put it in park it wants to die. Any ideas?

 

[BillGrissom]

When they idle poor, it is usually the other way around. They idle fine in P or N, but slow way down and shake in D. That is usually a lean condition. Since yours acts opposite, maybe you have a rich idle. Try adjusting the idle mixture. I am guessing your 2 bbl is not original since I thought the 2 bbl manifold (Super Six) didn't start until ~1976.