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Car Shakes with AC running

(2001 Ford Escape)
in Dallas, TX on March 17, 2009
I have a 2001 Ford Escape, v6. It has been a good vehicle but it is getting up there in its miles. The milage is currently at 93K.

Lately, the vehicle has developed a problem where it starts shaking like crazy if the idle is too low and the AC is on. You can normally compensate for this by hitting the gas a little bit, but this doesn't really work when stopped in traffic or making a slow turn.

The problem was not evident during the winter when the weather was cool, but since the spring has arrived the problem has popped up.

I had a similar issue last fall where the car would shake and shudder when cold started in the morning. That problem was corrected by servicing/cleaning the Air Intake System and also replacing the Idle Air Control valve.

The current problem is a lot rougher and more pronounced, as it only happens with the AC running.
Displaying 4 answers & 2 comments
Popular Answer
on March 18, 2009
I cannot find any technical service bulletins for this concern. There are a couple of conditions that we need to know, first when the engine starts to idle slow, do any noises occur? Second, does the alternator warning come on before the engine stalls or after it stalls. If a squeaking noise occurs when the AC is turned on, you may have an AC compressor starting to seize up internally. The engagement of the compressor clutch when the compressor is going bad will cause an excessive load on the engine causing the low idle speed. If the alternator warning comes on or the voltmeter (if equipped) reads low, it may have an excessive current draw from the electric cooling fans,(there was a recall to replace these fans). The last items that could cause this problem are electrical, there can be a loss of communication between the AC control module and the engine control module or a bad idle control valve. It is best to find a reputable shop to try to repair this due to the high cost of the parts related to any of these possibilities.
on August 07, 2010
I called my mechanic about the same problem. He told me that 99% of the problem is from the A/C being low on A/C Freon. The compressor is turning on and off and that makes the idle to go up or down. I went to pepboys and bought a do it your self kit and my idle problem went away. Plan to buy a few cans though.
on November 08, 2010
on March 25, 2010
Unplug the ac under the hood and see if it stops shaking. If it is caused by the ac it probably does it with the defrost on as well. The weather making a difference makes me wonder if it's your MAF sensor.
on April 22, 2012
my friend's 2006 Taurus would idle up and down with ac on. He said it wasn't very cool, so I charged it up a little and the idle stopped going up and down with ac on. I guess it was low on freon and the clutch kept kicking in and out causing the idle to surge.
on November 08, 2010
did check if you have any air leak in any of the hoses?. try to listen carefully when you open the hoop
dose the shaking happens like fast vibration or you feel something like "if you want to catch your breath after running."
when you shift it to D, any change in the shaking?
if you put it in P or N, and accelerate it. and good?
these happens with air leak.
fuel filter could be another reason.
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