Fuel delivery problems such as a dirty fuel filter, faulty fuel pump, faulty fuel pressure regulator.
Restricted exhaust such as a faulty catalytic converter, crushed/bent exhaust pipe.
A damaged catalytic converter could cause that.
Dirty fuel filter, dirty air filter, bad catalytic converter, restricted exhaust, insufficient fuel pressure.
will the transmission causes my 1999 ford expedition to bog down & sputter when accelerating the 4.6liter engine.
your powertrain control module is sensing major misfires while you are accelerating. i would suggest you replace the spark plugs and wires and if that doesnt solve the problem i would replace the coils next.
the engine timing could be off. Or, the fuel mix is wring. Or, the choke is sticking and the carburetor jets are out of adjustment.
when kick down the gas pedal to accelerate, the car downshift but then stalls and then engine stays rough until i turn off the engine and restart it then the engine runs normal again till the next kick down.
If this is a general noise, it could be the transaxle. When you are accelerating, the engine is pushing the gears, and when you let go of the pedal, the vehicle starts to shift back down. If this is an engine noise, it could be predetonation or a valve problem.
By D-accelerating
Sounds like the brushes are worn down in the alternator.
If it were accelerating due to gravity it would be vectoring down.
It could possibly be that your brake pads or brake shoes have worn down to the metal
An object that is accelerating may be slowing down, gaining speed, and changing direction.