78 D100 Keeps Shutting Off

[wayfarerstranger]

my 78 Dodge D100 slant 6 keeps shutting off when i slow down or come to a stop , not everytime but if it idles for to long it will shut off , has new fuel pump , air and gas filters , battery , voltage reg. and i cleaned out the carb . any idea`s " carb problems ,,, battery cables ??

[greg g]

How much does your key ring weigh???  If your vehicle is high miles and you have been driving around for years with 5 pounds of keys on you ring, I have seen vehicles shut off going over bumps, making sharp turns, making hard stops, all from the key ring wiggling out of the ON position, due to the pendulum effect of the wieght working against the worn mechanism. 

[Don Coatney]

Is there a torque convertor lock up on this truck that is not unlocking at idle?

[wayfarerstranger]

i only have one key but it weights 40lb`s      it is a 3 speed        it has improved a little the more i work on it   it is worst at first start up   seems to do better after warmup  ..  it has to be sometihing in or around carb      choke     vacuum  ? if ya tap gas pedal  it helps to keep it running  i also turned the idle up

[greg g]

Check for air leaks in the intake at the carb to manifold and at the manifold to head.  Had a Volvo that did similar years back, turned out the intake manifold was loose and sucking air.  I replaced a lot of parts before I hooked up the vacuum gauge and found it only pulling 12 to 15 inches.

[wayfarerstranger]

good advice

[Merle Coggins]

Does it make a difference if you are stepping on the brake pedal? A bad brake booster can cause a vaccum leak when activated.

[ptwothree]

check the throttle shaft for wear.  Squirt a little starting fluid or propane (unlit) around that area, when it's running, and see if the idle changes.

[wayfarerstranger]

will do  thanx