Highway speed jerking/bucking
 

Hey guys, Ive searched the forums and been able to find very little to help me with my issue save the possibility of bad plug wires...(Witch may be it or a seperate issue because of my recent terrible MPG.)
I have a 2005 Fx4 Level II 4.0 L. It has about 55,000 on it.

Lately, I have been noticing a single jerk or buck every so often when cruising at about 55-60 mph.
Seems to be getting more frequent and it varies in intensity.
It SEEMS to only happen when load(gas) is applied/unapplied and when in overdrive. Otherwise the truck runs great.

Does not SEEM to be transmission slippage..seems more like a bind or something
No Tach surge at all..no lights. possibly a tiny Clunk.
Does it in 4 or 2 WD.
only thing changed is the recent addition of a K&N Filter. MAF?
Could this be an issue with the factory locker?(Notice it more when it is very cold outside)

Truck has always felt like it is dragging a sack of potatoes...figured it was nature of the beast.
Thank you in advance for any info.

Re: Highway speed jerking/bucking
 

possibly sticking brakes?

Re: Highway speed jerking/bucking
 

My 96 ranger does this buck every so often, usually when in 5th gear going up hill or under big load. Almost like its started to lug out.

You say it feels like your dragging a sack of potatoes, is it possible the ebrake is partially engaged? either at the wheel or with the foot pedal? and the light is not on?

Re: Highway speed jerking/bucking
 

on my 90 that i had, the truck would do something similar now that i think about it, it turned out to be the rear end had chipped a ring tooth, and then the whole rear end went BOOM a few months later...

Re: Highway speed jerking/bucking
 

I had a 93 XL that did that and it was plugs,wires and a bad coil pack. Check them but with only 55k on your truck that may not be it

Re: Highway speed jerking/bucking
 

Well, no brake light..no lights at all.
I will have to pull the wheels and check for irregular brake wear.

If it does happen to be like a chipped pinion gear..I guess I find out when it goes boom..lol
for S &G's Im gonna do a tune up and see if that makes a difference...Ill post results soon. Thank you.

Re: Highway speed jerking/bucking
 

does it happen to only do it when it snows?

Re: Highway speed jerking/bucking
 

I have only noticed it with snow yes...first time it did it, it had just begun to snow....there was a dusting on the road...today, there was melting snow...mostly wet pavement...and high winds...could that be a factor?

Re: Highway speed jerking/bucking
 

mabye its your locker engaging due to some slippery conditions?

Re: Highway speed jerking/bucking
 

have you serviced the trans? it about due..

Re: Highway speed jerking/bucking
 

http://www.fordrangerforum.com/4-0-s...hen-snows.html

check the link. you maybe having the same issue

Re: Highway speed jerking/bucking
 

Dude, thanks, that sounds very similar...I'll investigate

Re: Highway speed jerking/bucking
 

Hi all my 2002 ford ranger is also doing this , one thing i noticed is it only does it when it snows even very slight. i thought it was bad gas so i used heat gas treatment and it would seem to go away . then it would come right back next time it snowed. i checked to make sure nothing was unhooked I.E like the hose from the air filter and such nothing was unhooked. it has about 159000 on it but other then that runs great. Im glad to see that im not the only one having this issue so maybe i can get it resolved . any help would be much appreciated!

----------

also there is no snow build up on the ground at all just flying in the air .

I have since figured out that it was indeed the k and n filter and snowflakes..replaced with a paper filter for winter and problem resolved. Thanks guys!!

Re: Highway speed jerking/bucking
 

If it starts again check your fuel pressure. If you have low pressure the truck will feel slow and misfire.