2000 Ford Taurus Rough idle and stalls when the A/C is on

MYCARFIX

MEMBER
2000 FORD TAURUS
6 CYL
FWD
AUTOMATIC
10,300 MILES

I have a 2000 FFV Taurus that started idling rough about a month ago. Since then I have used fuel treatment, installed new plugs, wires, and air filter. This has helped some. A few days after installing everything the engine light came on showing code PO174. At that time I found and replaced a cracked pvc hoses. The next day the car started going up and down in rpm, between 400 to 1200, and eventually will stall. But this only happens when the a/c is on. When ithe a/c is off it does not do this. I have even removed the serpintine belt and still have the same problem with it off but the switch on the dash turned to a/c. Other than this the car drives fine. Does anyone have any ideas?

Tuesday, November 18th, 2008 AT 7:23 PM

3 Replies

ZACKMAN

MECHANIC
4,202 POSTS

A code P0174 may mean that one or more of the following has happened:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak downstream of the MAF sensor.

Possible Solutions

* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Take it off and spray it with electronics cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling.
* Inspect all vacuum hoses, replace if necessary.
* Check for a dirty fuel filter and proper fuel pressure. Make sure that you get fuel filter that is meant for flex fuel.

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Tuesday, November 18th, 2008 AT 9:41 PM

MYCARFIX

MEMBER
2 POSTS

I tried cleaning the mass air flow sensor and the idle air contol valve. This made no improvement at all. By sheer dumb luck, I forgot to connect the plug back up to the MAF sensor after a second cleaning and the check engine light came on. When I went to disconnect the battery to see if this would cut the light off, the ground post on the battery moved slightly. Upon farther inspection it looked cracked about half way through were it met the top of the battery. After, replacing the battery the rough ilde and stalling is gone. I am guessing, maybe because of this the ecm was not grounded properly.

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Wednesday, November 19th, 2008 AT 3:41 PM

ZACKMAN