• Welcome to the Contour Enthusiasts Group, the best resource for the Ford Contour and Mercury Mystique.

    You can register to join the community.

Intermittent bucking

K

KingpinSVT

Hard-core CEG'er
Joined
May 21, 2003
Messages
2,634
Location
Ocala, FL
So lately Ive been getting some bucking between 2-3k RPM. Its very intermittent. I have trouble getting it to repet itself on every accel, but I usually notice it between 2-3K and usually above 1/3 to 1/2 throttle (been most noticeable in second gear around town. I dont notice it in first). Its been getting a bit more frequent and worse over the last week or two. The more throttle it has, the worse it is.

My plug wires are fairly new (in the big picture), but are Magnecors and I know people have had problems with premature failure lately. My fuel filter and plugs have also been replaced recently enough that I wouldnt look there first (though I suppose some bad gas could have ruined the fuel filter already). Ive also searched the old site, and found that it could be any number of issues: fuel filter, fuel pump, dirty fuel pump sock, dirty MAF sensor, wires, coil, etc.

I did clean my air filter recently, so Im hoping that the problem is that some oil may have found its way to the MAF. I didnt think it was over oiled, however. Im going to check that first anyway (very cheap and easy). Im not sure if this could cause bucking in such a small window, I would think it would affect more of the RPM range.

Basically Im wondering what could be the most likely causes. Im going to start with the cheap and easy stuff unless someone has another idea or gives me easy ways to check things like the wires.
 
If you are not getting any CEL codes, I would look at changing the gas station and fuel octane to see if it helps.
 
No CELs. It is definitely dependant on throttle position though. Light throttle and no bucking.

I rarely use the same gas station twice in a row, but I do always buy Shell and I guess all in the area get the same supply though I doubt the shipment was bad.

Tomorrow Im going to start throwing cheap fixes at it that wont hurt to do anyway (even though some items arent that old). Clean MAF wires, new plugs, new fuel filter. If it continues Ill move to checking the fuel pump sock, then wires and fuel pump. Start cheap and move forward. At least its not that bad. . . .

Thanks for the reply Tony.
 
Not trying to thread jack but I have an identical problem. I am throwing the P0420. I have very new plugs,wires,fuel pump,and fuel filter. Hopefully together we can narrow down what might be causing this problem. I wish I had a scanner because it is weird that the problem is very intermittant. Ive been thinking TPS lately but havent really checked into anything. But that CEL light just came on yesterday so maybe a bad O2? Also I only use Shell Premium.
 
After shooting around the block, its definitely not intermittent. It is load dependent, and only happens between certain RPMs. It feels like its a stumble almost. Hmmm.

Off to the parts store. Im beginning to suspect my wires.
 
Could it be your transmission?

I had a problem with surging, and it turned out to be the fuel filter. Rather than changing everything at once, try changing a part at a time to see if you can isolate the faulty part.
 
Definitely sounds like a fuel pump problem, Chris. If I were in first or second and jabbed the throttle ,it started bucking or bogging. As soon as I changed out the pump for the Focus one, it stopped.
 
Thanks for the suggestion Mike. It actually turned out to be my Magnecors taking a crap. I was removing them to just start checking things out (Ive had my suspicions since re-reading what happened to Todd) and one of the boots snapped in half. So, I went and bought new plugs and wires and now the bucking/hesitation is gone. One of the plugs looked like there might have been some arcing or corrosion as well. :shrug:

The fuel pump was on my list, but further down as its more expensive. I figured Id try the easy stuff first and if it didnt work then move on to more expensive options like the fuel pump or wires. Luckily the awesome quality of the Magnecors gave me a shortcut.
 
I'm having the EXACT same problem going on right now, bucking under 3500 RPMs and 30% throttle or more. As soon as 3500 comes rolling around it stops. Magnacore wires are under warranty if they were purchased 8/06 right? Also they have like 2500 miles on them, has this been even heard of? Magnacore's taking a crap so soon?
 
Last edited:
Ooooo...Me too

Ooooo...Me too

Not that I want to freak anyone out here...but I see Im not the only one to suspect tranny issues. Im glad it was something simple for you...but this problem seems to be a regular...and I think has a variety of possible conclusions.

My 97 SE did this for quite awhile before it went all haywire. I had a new fuel pump, so it wasnt that. I had that proactively replaced about a year ago.

My car kicked me when I was below 2000RPM. Especially on inclines. Then it started doing it even without an incline. Then one day, it started revving. I would be driving along and the thing would drop to 800, kick and go to 6000...and back and forth.

I called Ford on this and the first thing they asked was if I had recently flushed the tranny. I had. This apparently was the death of the tranny. And a $3600 repair. Woe is me.

Just wanted to post for those that have eliminated the possibilty of mags or fuel pump.
 
Maybe the borg-warner wires I used were no good, I was also expecting tranny but it may be worth it to first try another set of wires.....
 
I have had wires crap out that quickly... Ford Racing crappy wires! Try Taylor thundervolt 8.2mm wires! Only $55 shipped or so from Autopartswarehouse.com.



Jeff
 
You must log in or register to reply here.
Back
Top