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


Asked by Aug 24, 2015 at 09:51 PM about the 1977 Ford F-250

Question type: Maintenance & Repair

I know I have some carb issues. I don't
know if they could be related.

8 Answers


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


There is a vacuum modulator on this transmission, so if the vacuum is not right then it can have an effect on the shifting of the transmission, it is possible that the needle and seat are leaking fuel into the bowl just enough that when you slow down it floods out the engine. Has the carb ever been overhauled with the new seals and gaskets that will allow you to run this garbage they call fuel today? If not now would be a good time to consider having it done. Make sure all of your vacuum hoses are in good shape and your fuel hoses are of the new mulit fuel style or you will wind up back in there cleaning out the little rubber particles from your hoses that are being eaten up from the inside. HTH


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


Still doesn't sound like the carb is setup correctly, I had one of those trucks back then, if it's setup right when you first push the gas pedal one time cold it sets the choke and the fast idle crank it over and it will fire right off let it idle a few about 30 seconds, tap the gas pedal and it will drop to mid idle step, and you can drive away with that idle. After it's fully warmed up it should be idling smoothly at around 650 RPM in gear, same if you have the anti diesel solenoid setup. Sorry about the pea poor repair job on the trans, have you tried to take it back yet? I really liked my truck when I had it, used it to haul wood mostly, never could get good mileage though, the mileage was 9 MPG, didn't matter if it was loaded or empty, city or highway, it was 9, my Dad brow we'd it once to move with, he put cab high rails on it and loaded it cab high all the way back, then hooked up a double axle trailer full of his stuff, ran it over the scales it weighted 13500 Lbs truck and trailer and he got, you guessed it 9 MPG. so get then to reset that carb properly and it should straighten out and run properly. HTH.


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

1 out of 1 people think this is helpful.

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


No, a gas engine is for gasoline, a Diesel engine is for diesel.

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