# 2003 Ford Taurus speedometer fluctuates on idling, car sometimes stalls out **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** ford, taurus\ **Created:** [November 7, 2013, 1:19am UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115 "2013-11-07T01:19:21Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![AComer](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AComer](https://community.cartalk.com/u/AComer)\ **Post date:** [November 7, 2013, 1:19am UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115/1 "2013-11-07T01:19:21Z")
my 2003 ford taurus SES radomly has problems with the speedometer fluctuating from 0 to 10 mph upon idling. Sometimes the car will eventually stall out but always restarts without a problem. You can feel it “jerk” when changing gears or what I describe as a “hesitation” once in awhile. The car is an automatic and we have already replaced the relay and the voltage regulator/alternator - that has not helped. I can’t afford to keep throwing money into it replacing parts that don’t fix the problem. Any ideas on what could be wrong? ---
**Author:** ![croneeng](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@croneeng](https://community.cartalk.com/u/croneeng)\ **Post date:** [December 11, 2013, 2:22am UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115/2 "2013-12-11T02:22:45Z")
I have the exact same problem in my 2003, but solved the stall issue with a new ignition module. What gives with the speedometer? The odometer also clicks tenths off while waiting at the stoplight! Also noticed a high pitch sound when the problem occurs. Help! ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [December 11, 2013, 6:11am UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115/3 "2013-12-11T06:11:20Z")
Is the Check Engine light on? Tester ---
**Author:** ![croneeng](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@croneeng](https://community.cartalk.com/u/croneeng)\ **Post date:** [December 11, 2013, 9:04pm UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115/4 "2013-12-11T21:04:00Z")
Tester! No, the check engine light is not on, and when I plug in the OBDII reader, there are no faults. I did notice the lights flicker as the speedo needle bounces while the engine is at idle. As a test, I pulled into a parking space this morning and the needle fluctuated wildly and I heard a whine like the alternator was at max load. When I restarted the car a moment later, all was normal, like restarting reset the voltage regulator. I checked the temperature of the wires at the battery and alternator, they were not even warm so there doesn’t seem to be an overcharge condition. I’m suspecting a bad diode in the alternator…your input solicited! Dave ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [December 12, 2013, 12:07am UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115/5 "2013-12-12T00:07:50Z")
Have the alternator tested. The regulator is contained within the alternator, so they’ll be tested together. Yes, a blown diode is a good candidate. ---
**Author:** ![croneeng](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@croneeng](https://community.cartalk.com/u/croneeng)\ **Post date:** [December 25, 2013, 9:51pm UTC](https://community.cartalk.com/t/2003-ford-taurus-speedometer-fluctuates-on-idling-car-sometimes-stalls-out/82115/6 "2013-12-25T21:51:45Z")
It was in-fact a blown diode. The new alternator fixed the problem!