99 ford taurus

mcdonaldf · 06-12-2009, 12:24 PM

My transmission downshifts out of overdrive if I touch the gas pedal even lightly. Also the tach drops to zero when not accelerating. The spedometer is stable. Could this be my speed sensor

**mack1** · 06-12-2009, 06:45 PM

Hi mcdonaldf and welcome to TSF,

The term speed sensor usually means the sensor at the transmission output that tells the vehicle speed. Engine rpm is taken from another sensor and that one might be problematic. I think the same sensor that looks at the cam gear for the spark is used for the engine rpm also. I think Ford calls that sensor VRS (Variable Reluctance Sensor).

The only print I have that shows that is for a 1990 4.0 L engine. A Tach signal goes from that module to the instrument cluster.

If you have electrical prints for your car, you can post them here and we will help you track down the problem.

Very Best Regards,
Mack1

06-12-2009, 12:24 PM	#1 (permalink)
mcdonaldf Registered User Join Date: Jun 2009 Posts: 1 OS: win xp	99 ford taurus My transmission downshifts out of overdrive if I touch the gas pedal even lightly. Also the tach drops to zero when not accelerating. The spedometer is stable. Could this be my speed sensor

06-12-2009, 06:45 PM	#2 (permalink)
mack1 TSF Articles Team Join Date: Nov 2007 Location: Texarkana, Texas Posts: 1,245 OS: xp sp3 My System	Re: 99 ford taurus Hi mcdonaldf and welcome to TSF, The term speed sensor usually means the sensor at the transmission output that tells the vehicle speed. Engine rpm is taken from another sensor and that one might be problematic. I think the same sensor that looks at the cam gear for the spark is used for the engine rpm also. I think Ford calls that sensor VRS (Variable Reluctance Sensor). The only print I have that shows that is for a 1990 4.0 L engine. A Tach signal goes from that module to the instrument cluster. If you have electrical prints for your car, you can post them here and we will help you track down the problem. Very Best Regards, Mack1 __________________ "If you like yourself others will like you also" me "Don't drink downstream from the herd" Will Rogers Submit New Articles Here