Hi, I am John Mc, a Ford dealer technician.I hope I can help solve your problem quickly and accurately.
Please wait a moment while I work on your problem.
It sounds like you have a vacuum leak. This was probably your issue all along. Find the pcv valve in the passenger side valve cover and follow the vacuum line to where in goes to the intake. The elbow that connects to the intake is bad about rotting out and causing your whole problem. If this is the case go buy a new pcv tube from a dealer and you should be set.
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No, thats not it I have checked the PCV Valve and its connecting elbow, no leaks detected.
Ok then, my next suggestion would be to remove your maf sensor and use some carb cleaner or brake cleaner to clean out the internal electrical part throughly. Take the battery loose while doing this so it can recalibrate the sensor when reconnected. You may just have a bad reading on your maf sensor causing the whole problem.