2000 Ford taurus jerking above 65mph

[taylor021]

My Taurus is jerking whenever i am accelerating above 65mph. I thought it was the fuel filter so i replaced that and it still happens. I have attached the video of the problem, the whole time i am holding the accelerate on my cruise but it does it with the foot on the pedal to. any help would be appreciated! http://www.youtube.com/watch?v=-x9YJmVTk_M

[shorod]

Did you step on the throttle to get it to downshift, or did it do that while you were accelerating at the same rate as earlier in the video? It acts a lot like a car with a misfire, probably either a bad spark plug or spark plug wire. How long's it been since the car had a full tune up? Also inspect the intake air tube to make sure it's connected properly and there are no cracks in the expansion accordion area that may be opening as the engine moves when the transmission shifts.

-Rod

[taylor021]

the whole time i am holding down the accelerate button. wouldnt a misfire trigger a blinking check engine light?

[shorod]

Have you checked for pending codes? The CEL with a P030x code will only trigger if the misfire counts are above a certain number per 200 revolutions (or something like that). Since your car's issues seem to only occur under heavy load and acceleration, if they are misfires they may not be exceeding the threshhold. On my prior 1998 SHO I had 4 coils fail at 4 different times, none set a CEL. I could feel the misfires though and in the Component Parameters listing of my scan tool I could see misfire counts on individual cylinders, but the counts were not high enough to trigger the CEL. Each time I replaced the coil for the indicated cylinder and the misfire went away.

-Rod

[taylor021]

ok new info. today i replaced the spark plugs and checked the wires. the problem still happens. to make sure it had nothing to do with the automatic transmission i put the vehicle in 1st gear and got the rpms up to about 4,000, when it gets up that high the jerking starts. so my guess is it has something to do with the fuel system. is that right?

[shorod]

Not necessarily. Is there a reason you didn't also replace the spark plug wires? How did the spark plugs that you removed look? Were there any that looked different than the others? You may as well change the fuel filter while you're at it, and before going to the parts store, check the air filter in case it is dirty as well.

If you're convinced it's a fuel problem, check the fuel pressure. It may be a bit tricky to check the fuel pressure when it starts to act up, but checking it KOER and KOEO should give you an indication of if there is a problem with fuel pressure.

-Rod

[taylor021]

what does KOER and KOEO stand for? i replaced the fuel filter and checked the air filter and it was fine.

[shorod]

KOER = Key On Engine Running
KOEO = Key On Engine Off

-Rod