2003 4.6 v8 infamous bucking

[Rossthab022]

Hi everyone I have a 2003 ford explorer with a 4.7 sohc v8. Recently it just started buckin at steady rpms and under load. The service engine soon light has come on and I'm throwing misfiring codes in cylders 6 and 7. I have read a lot into this and can't decide what to do because I still owe quite a bit of money on it. The bucking didn't start till after I got new spark plugs put in. I've heard that it could be aray of things. I've heard it could be bad spark plugs/coils, cam shaft position sensor(what does that do) or just bad gas. I'm going to replace the fuel filter and do a tranny flush soon and hopefully that fixes but I doubt it. I had it smoke tested or whatever and no leaks. So all in all what the hell is wrong with it? Anyone else have the same problem that could help me out?

 

[Turdle]

I moved this thread to the 3rd gen forum for more views. Even so you need to give it some time for a good answer.



Not sure what happened, your second post was actually a second thread. I tried to merge them and the last post went to the top.


Edit--there, I think it is cleaned up now.

 

[n2epv]

I had the same thing with my '04 V8. It would only skip under load - around 55 MPH in overdrive. I was getting misfire codes for two cylinders. The plugs looked fine (original plugs with about 65K miles, didn't replace the plugs). Replacing the coils for those two cylinders that had the misfire codes did the trick. It must have been a weak spark caused by those coils starting to die.

I've heard people replacing all 8 coils as part of a tuneup, and will be replacing coils and plugs soon as it now has 75K miles on it.

 

[Bruce Thompson]

I had the same problem after replacing plugs ( miss fire with one of the cylinders with code p0303). As it turned out I had dirty spring at the contact with the spark plug. I cleaned the coil spring really well with carb cleaner. I suggest you do this - 1) remove your COP's, 2) remove the cop boots, and 3) clean the spring tips with carb cleaner. When you put it all back make sure the connector is seated properly ( making click sound and locked in position ). Disconnect the negative terminal on battery to reset the computer. This would be a cheap fix. Good luck.

 

[Rossthab022]

I've also heard that it could be the auto 4x4 kicking in. My tires are nearly gone all around which supposedly causes bucking. I think its called the brown wire mod or something. I think you cut the brown wire running to the transmission and run it to a switch in the cab?