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-   -   Truck Jerking/Studdering Around 45-50 mph (https://www.ford-trucks.com/forums/1017128-truck-jerking-studdering-around-45-50-mph.html)

Shane Cummings 12-06-2010 01:32 PM

Truck Jerking/Studdering Around 45-50 mph
 
Hello all. Here's a little information about my truck. It's a 2000 F-150. Two wheel drive. 5.2 Liter V8. About 133,000 miles on it currently.

Here is the problem I have been having with it recently. Right around 45-50 mph, my truck starts to jerk or studder as I attempt to accelerate gently. It has not been too bad, but it has been prevalent for the past few months. Yesterday, after an 8 hour drive on highways, when I got back onto a regular road, the truck would jerk/studder around 45 mph and it was so bad that I could not drive past 45 mph.

It does not always happen when I drive, but now it is occurring more frequently. I want to bring it into the shop, but want to hear what you guys have to say about this problem first. Thanks!

phil6608 12-07-2010 11:23 AM

Is the check engine light on? If so can you have the codes read?

Shane Cummings 12-07-2010 08:45 PM

Nope, the Check Engine light is not on.

Outdoors4life 12-07-2010 10:34 PM

Even though the CE light is not on there may still be a code. Last week my #8 cylinder was not firing and it threw a code but did not turn the CE light on. Try checking for a code anyways.

Shane Cummings 12-08-2010 01:39 AM

How do I check for a code?

Outdoors4life 12-08-2010 05:17 AM

Need a code reader. Some auto parts stores will check it for free.

Bluegrass 7 12-08-2010 11:24 PM

You may never get a code from the issue.
The problem is one or more faulty coils that are "not" hard faults so will not set a code you can see with a reader or see a light from.
Only other way is to use a good mid level "Scanner" to trap the fault or have the coils stress tested by a dealer to find any with low output.

Fyi to all: If you have any tendency to shudder under light loads at anythime, there is a high likleyhood of a low output coil.
Reason: Under low speed and light throttle on and off, the EGR system operation causes very lean air/fuel ratios that requires higher coil voltage to fire.
If one coil has low output, that cylinder will missfire until a shiftdown, higher throttle or any action causes the air/fuel ratio to become richer allowing the coil to fire again.
Then the shudder goes away until the next time.
This temporary condition does not set a code.
Good luck.

CharlieBravo 12-09-2010 08:07 PM

Get a scanner that can read any "pending" codes. These do not always trigger the CEL.

My 97 F150 had the exact sysmptoms you describe. Under light load at approx 40-45 the transmission went to bucking and got worse over time.

Only with the scanner was I able to get to the root cause. A cyl 3 misfire. Turned out to be the plug wire. 5$ fix.

97flairside 12-10-2010 06:12 AM


Originally Posted by CharlieBravo (Post 9665551)
Get a scanner that can read any "pending" codes. These do not always trigger the CEL.

My 97 F150 had the exact sysmptoms you describe. Under light load at approx 40-45 the transmission went to bucking and got worse over time.

Only with the scanner was I able to get to the root cause. A cyl 3 misfire. Turned out to be the plug wire. 5$ fix.

Wait, so you were experiencing what felt like the transmission bucking or slamming around and it turned out to be the coils? I am experiencing the exact samething, happens usually when under load or cruising. It gets so bad that i have to wait for the rpms to stop dancing on the guage before I can continue. Happened 5 times today alone trying to get to work.

If I have a 4.6L with the 2 coil packs, could I be experiencing the problem with misfiring?

Joe Finn 12-10-2010 07:28 AM

Don't rule out torque converter shudder. Has the trans fluid ever been changed? Changing the fluid usually cures it.

97flairside 12-10-2010 07:39 AM

oh this is wayyyyy beyond torque converter shudder. I've felt that. I did have the fluid changed back in October 2008, about 25,000 miles ago.

CharlieBravo 12-10-2010 07:09 PM

GET THE SCANNER!!!!!!!!

Throwing parts at the problem will nor resolve! I too have the 4.6. The bucking was caused by a bad plug wire. I thought it was the tranny as well. Mine has 260k and was thinking tranny rebuild.

The CEL never came on. The p0303 code would show as pending and would go away a few seconds later. Drove me nuts looking for the problem. The scanner solved the mystery in a few seconds.

Bluegrass 7 12-10-2010 07:16 PM

Agree.
Get off the transmission shudder kick for this kind of drivability fault.
The hint is 45 to 60 mph and light throttle application.

97flairside 12-10-2010 08:14 PM

an autozone scanner will be able to pull up pending codes?

CharlieBravo 12-11-2010 10:37 AM

Another Question........

If you turn off OD does the shudder still occur? Mine was caused by the OD dropping and shifting back.


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