Bucking Bronco!

[Greg French]

My D1 is bucking down the road while under load. It gets up to around 2000 RPM, then starts losing power. Throws misfire codes...usuallu 5&7.

Over the years, I have replaced the plugs, wires(this helped for a few months), fuel pump, fuel filter, some injectors, vss.

What else could be causing this?

 

[Disco Mike]

TPS, MAF, fuel filter and O2 sensors will all cause that to happen.
Mike J.

 

[Greg French]

Oh, yeah...Changed the TPS, too.

 

[cbass]

What do you have the spark plugs gapped at? Sometimes too big of a gap will cause misfires. I would try playing with that. I don't know what mine are gapped at, but I'm sure someone on here would know what runs the best in these engines.

 

[rpm2429]

Cleaning the Stepper Motor about three times cured my D1 from doing that same thing, and it has not returned in over 30k miles. Good Luck, Ron

 

[greendisco1]

3 words VEHICLE SPEED SENSOR it is located in the rear of the t-box near the e-brake i think 4 or 5 mm allen bolt when the sensor goes bad it will only throw odd bank misfires and the vehicle will buck like you are talking about usually at highway speeds if you can freeze frame data that is stored in the ecu you would see something like a speed of 120 mph. at 2000rpm witch is cause by a wacked out speeed sensor

good luck

 

[Steve83]

Could also be coils. Have you checked them or the codes?

 

[Rocky]

A bucking Brocno is a well documented adverse reaction caused by Ford buying Land Rover.....

 

[Steve83]

Watch it, now...

 

[Greg French]

Not the VSS in this case. Easy way to check the coils?
Changing the plugs today just in case.
Got Magnecore wires. Second set, in fact.

 

[Steve83]

Use a cheap spark gap tester set to ~25kV to see if the coils are breaking down. If the spark is intermittent, you have a bad coil. Check all 8.