erratic speedometer, strange take-off
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erratic speedometer, strange take-off
OK guys, here's a good troubleshooting exercise:
I have a 95 F150 2WD, with the 4.9L 6 cyl. Speedometer is very erratic past approx. 40 MPH, (spiking 20-30 MPH!) and the engine tries to die out and then comes back on take-off (manual tranny).
Also wants to die when coming to a complete stop, just like on take-off.
Self testing shows error code 212 relating to engine TACH signal or SPOUT circuit. So far, i have replaced: TPS, RABS speed sensor, Ignition Module, and tested the coil.
The really fun part is: if I unplug the RABS speed sensor completely, the truck runs fine.
I'm currently looking for directions to test the SPOUT circuit or any other (related) ideas - I have about driven myself nuts trying to troubleshoot this. Any suggestions would be greatly appreciated!
I have a 95 F150 2WD, with the 4.9L 6 cyl. Speedometer is very erratic past approx. 40 MPH, (spiking 20-30 MPH!) and the engine tries to die out and then comes back on take-off (manual tranny).
Also wants to die when coming to a complete stop, just like on take-off.
Self testing shows error code 212 relating to engine TACH signal or SPOUT circuit. So far, i have replaced: TPS, RABS speed sensor, Ignition Module, and tested the coil.
The really fun part is: if I unplug the RABS speed sensor completely, the truck runs fine.
I'm currently looking for directions to test the SPOUT circuit or any other (related) ideas - I have about driven myself nuts trying to troubleshoot this. Any suggestions would be greatly appreciated!
Senior User
Joined: Feb 2000
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erratic speedometer, strange take-off
Do you have cruise control? It could be kicking on somehow, pulling on your throttle erratically. It's just a wild guess. You could disconnect the cruise cable from the throttle cable, and see that gets it. Just an idea...
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Joined: Jan 2001
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From: Virginia
You may have problems in the rearend, causing metal shavings to get stuck to the sensor. Pull it out and look at it. Also check the wiring for corrosion at the sensor.
Code 212 does have something to do with the dist though. I would check the wiring at the dist. One of those wires has a shield, and it can get against the signal wires.
Code 212 does have something to do with the dist though. I would check the wiring at the dist. One of those wires has a shield, and it can get against the signal wires.
Last edited by Franklin2; Sep 10, 2007 at 01:38 PM.
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Joined: Sep 2007
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Franklin2 -Thanks for the reply however that was campbell2 that had the code 212 error. The chaeck engine light has never come on so I assume that mine dosn't have any error codes, I will check that ABS/Speed Sensor for metal shavings and clean it see if that helps. Thanks
