I Had My Car Looked at by 3 mechanic none of them could figure it out..
The symptoms are ill be driving and the rpms would buck down to 0 and then back to normal real fast sometimes it would repeat for like 3 seconds...
And sometimes the car just shuts off and i dont even know it shuts off till i turn the wheel or step on the gas...
this has been going on for months... no machine can pick it up cause the problem has to be happening for the machine to pick it up...
And My Car Has Been Lacking Alot of horse power..
Any Ideas...???

 

My car was doing the same thing, I replaced my IAC valve and it hasn't done it since.

 

What mods have you done, if any? I second the IAC valve as well.

 

i took it to the ford dealer and it turned out to be a Bad Fuel Pump Module

I Have
Mac Headers
Mac Cold Air Intake
Flow Master Exaust System
Msd Coil


BBk Pulleys And 3:73 Gears Getting Installed This Weekend