studder when coasting down on highway
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Junior User
Joined: Jul 2009
Posts: 58
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From: wi
studder when coasting down on highway
well, yet another issue with the 2000 f150 5.4 4X4 that i just bought. today, it would feel like it missed a beat or studder once when coasting from 65 down to 60. it seemed to do this when i was going down hill and had my foot off the gas. when i would touch the gas again, very lightly to maintain speed, it would studder once. it was almost like the weight of the vehicle had been pushing the engine, and touching the gas took out the slack in the drive train, making it buck one time.
it did this 5-6 times within 15 minutes. would this be a sticky torque converter, or a cop issue? or ????
if it is the converter, this would actually be a good time for it to go out as i am having the flywheel replaced next week wednesday.
it did this 5-6 times within 15 minutes. would this be a sticky torque converter, or a cop issue? or ????
if it is the converter, this would actually be a good time for it to go out as i am having the flywheel replaced next week wednesday.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
You likely have a low output coil on one cylinder causing the missfire just at the time the driving conditions have the motor at it's leanest operating conditions.
Those being the EGR is open, the fuel is cut back and ignition timing is advanced.
The result is a very lean mixture one coil cannot fire until you call for enough power to exit those conditions and the fuel richens up, the miss goes away until the next time, then it cycles all over again..
Those being the EGR is open, the fuel is cut back and ignition timing is advanced.
The result is a very lean mixture one coil cannot fire until you call for enough power to exit those conditions and the fuel richens up, the miss goes away until the next time, then it cycles all over again..
Thread Starter
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Junior User
Joined: Jul 2009
Posts: 58
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From: wi
so, if i understand things correctly about cops, there is no real diagnostic to see which is bad. should i assume that #4 & 8 are the first suspects? and what about just changing the boot assembly? i see that advance sell just that kit and i have read here that the boot can be the problem
Senior User
Joined: Feb 2008
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sounds to me like the torque converter is doing its job. when accelerating the impeller and stator are locked together via clutch. when you touch the accelerator the clutch engages, and disengages when you take your foot off again. it also engages when it gets input from the brake light switch so you get some engine braking while decelerating.
