Jerky 2008 sport trac V/8

[montermahan]

I have a bump or jerk and don't know if it is in the trans or motor. I think it's the trans as it seam's to do it under partial throttle and around 60 mph. It jerk's like an engine miss, but I have never felt in in the lower gear's at the same throttle position. I wonder if it's the trans looking for the right gear to be in and kindov searching around? I wonder if a reflash would be my first option. I have 80,000 miles on it and plug's are factory. Thank's

 

[Exrange]

I had a similar problem, no check engine light and it turned out to be a coil. I had 83k when this happened.

 

[07LTDDSM]

i'm just under 70k with the same problem. how did you go about detecting which coil pack was bad?

 

[montermahan]

I changed the plug's (Got all 8 out without breaking any off) drove it about 50 miles and didn't have the problem, but it has been intermittent in the past. hoping the plug's fixed the problem.

 

[Tech By Trade]

Coils are notorious on those things too. I know guys who will take any they can find any time they go to the wreckers.

 

[diesel_s]

Its coming from the coil packs, the problem isn't from the transmission. I bought my ST with 60K on it and during the test drive I told the dealer to find out why its jerking or else I'm not purchasing the ST. They took it in for repairs and it turned out to be 3 of the coil packs. I'm having a slight shutter now around 55 mph - 60 mph...Just to test it to see if its the trans or the motor, i let the vehicle shift through all of its gears at low rpm and no matter what gear its in, it does it at the same speed every time. I'm actually changing out the remaining 5 coil packs in a week and changing the spark plugs tonight.