Sorry for the long post, but please read! I am new to working on my truck and could use some advice from any patient experienced forum members.

The whole problem began in December last year after I had made a 400 mile road trip from Maryland to Massachusetts. The next day after I arrived I went to drive my truck and it began bucking like a bronco at around 40mph. I had no idea at the time what was wrong and thought I may have blown a tire because of the violent shaking. I pulled over and shut my truck off and got out only to find nothing visually wrong with the tires. When I tried to start my truck it rolled over but didn't start. I gave it another crank and with a little bit of hesitation the truck started. I immediately drove it home and put a voltmeter on the battery and found that when started the voltage was relatively low. I went out and purchased a battery and the problem seemed to be resolved and was able to drive home with out any noticeable problems or codes.

About a month later it started bucking again around 50mph and eventually I received a single misfire code. It seemed logical to me if my battery was running low back in December that a misfire would be more noticeable. So I replaced all the plugs and coils and found that there were several boots which had deteriorated and ripped. However after replacing them all it still hasn't fixed the problem except I no longer have any codes showing up. Please remember I am new to working on trucks and might need some patience as I may not know what you are talking about but am eager to learn.

Cheers,
Jared311
2003 F150 4.6L 4WD

 

I forgot to mention that I have also replaced my fuel filter and ran fuel injector cleaner through the gas tank recently and there was no noticeable improvement.

 

Well dang, I was hoping someone would be interested in helping me since this is a forum and all. I tried searching through all the similar threads and there are just way too many suggestions.

 

Simmer down playboy....ok if it bucking it's has to be a coil pack,plug,or injector problem.
Have your rechecked your coils? Unplug them one buy one and listen for a change in the engine running. This is a quick easy way to check them.That also applys to the injectors as well....one by one....just beacause you replaced your coils doesn't mean that you don't have another on that is fried. What kind of coils did you replace your stockers with?

 

hahahhaha srry that was funny, and maybe the reason noone has answered is because noone knows (i kno i dont) but sounds like westtnfx could be on to somthin

 

I know I will get flamed for this, but I purchased autolite plugs and coils... I didn't know I was suppose to go with motorcraft until after it was too late. Either way, I unplugged each coil one at a time and the bucking increased significantly for every single one.

So I guess this means either the problem is intermediate or possibly somewhere else? What's the next logical thing to try, the cylinder compression and distributor cap?

 

Hi Jared,
offer a bit more info, how many miles on the engine, how long have you owned the truck, is there anything that you do or can do to cause the problem to become worst or better, has your CEL, (check engine light) come back on, ect.
When you sy the problem is either intermitten or something else is something to question, cause only you can say if it is a ful time issue or just once i awhile.
But we have to determine if the problem is electrical or fuel.

 

I have owned the truck for three years and it has around 157k miles on it now. My dad was the owner before me, so I know he took good care of it as well.

Although I can feel the bucking at idle, it definitely increases significantly around 65 mph now.

Nope.

It seems to be intermittent because I definitely noticed an increase in bucking when the coil or fuel injector was unplugged. I also don't always notice the bucking around 65 mph but it seems to be a majority of the time.

 

More than likely the MAF sensor has given up. The symptoms you describe are identical to those in my granddaughter's '94 Ranger (164K). A new MAF sensor fixed the trouble.... $95-145 at Advance Auto Parts.

 

Is there any way to determine that before shelling out the cash?