77 ford f250 6.6 L 400m . When I'm coming to a stop and the AT down shifts it chokes out and dies.

Spray carb with a whole can of carburetor cleaner and check air filter replace fuel filter if have not done so in a while.

Hi 77, How does the engine start when cold (first start of the day) .. How does she run after the engine is warmed up (at idle in Park) ... any fluctuation in the engine rpm when stepping on the brake pedal (at idle in Park) ... Transmission losing any fluid (with no evidence of a leak) ... Does she have an Overdrive Button ... or (2) Drive positions on selector 1,2, D1,D2.. or 1,2,3 and Drive. Fill me in when you have a chance

It has a newly rebuilt Trans but the place I took it to wasnt the best and didn't put the access panel to the fly wheel on and got garbage in the slot put the wrong vacuum modulator on and there is a little what looks like to be a access panel on the passenger side above Trans pan that leaks "when running" about 1/2 a quart a day but I can't get to it without dropping the trans. So that's everything to do with the trans the carb is brand new took the old one to a performance shop to be rebuilt and they just got me a brand new one and it had a mechanical choke put a electric choke on. RcarsRnice When its on a cold start it doesn't like to stay running have to keep throttle about 2000 rpms to stay running once it's warm it can stay running and can go into drive and reverse fine but when I'm driving a stop at a stop sign or red light it just chokes out and dies It's a P N R 2 1 no over drive No change in rpms when i hit the brakes

Sounds like an issue with the choke ..she should start and idle when cold. are you familiar with the vacuum operated choke pull off ... cracks choke open 1/16 to 1/4 inch on cold start allowing enough air needed to run ....when she's warmed up check to see if choke is wide open take out a couple of spark plugs ..if they are completely black.(covered over with soot) choke is not opening when hot. ...tranny leaks are another issue but they wouldn't cause engine to stall

i have a 79 same engine and wondering if it could run on deisel or not