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Discussion Starter #1
I noticed yesterday when driving on the highway, that my Santa Fe jerked for a split second - in other words it seemed to have lost power for a split second. It never shut down, there's no CEL and continued driving fine for the rest of the time on the highway (about 5 minutes). I wasn't looking at the dash so I don't know what the gauges did, if anything.

When I got home, I was idling and happened to notice that the speedometer needle jumped up to about 40 for a split second then went back to zero. The engine stayed at idle the whole time. It may have skipped but I didn't notice.

I had a similar problem when I owned a Dodge and the cam position sensor was failing, causing the engine to do this exact thing, although when it happened on this car, it was the tachometer that spiked.

Cam sensor in the Santa Fe has never been replaced in the time I've owned the car (almost 6 years now). I replaced the crank sensor with OEM back almost 3 years ago.

Anyone else have this problem? Hooked up the scanner but no DTCs were logged. My daughter drives the car and I don't want it to be a safety issue. I'd like to get it fixed before she heads back to school.

Thanks!
 

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I noticed yesterday when driving on the highway, that my Santa Fe jerked for a split second - in other words it seemed to have lost power for a split second. It never shut down, there's no CEL and continued driving fine for the rest of the time on the highway (about 5 minutes). I wasn't looking at the dash so I don't know what the gauges did, if anything.

When I got home, I was idling and happened to notice that the speedometer needle jumped up to about 40 for a split second then went back to zero. The engine stayed at idle the whole time. It may have skipped but I didn't notice.

I had a similar problem when I owned a Dodge and the cam position sensor was failing, causing the engine to do this exact thing, although when it happened on this car, it was the tachometer that spiked.

Cam sensor in the Santa Fe has never been replaced in the time I've owned the car (almost 6 years now). I replaced the crank sensor with OEM back almost 3 years ago.

Anyone else have this problem? Hooked up the scanner but no DTCs were logged. My daughter drives the car and I don't want it to be a safety issue. I'd like to get it fixed before she heads back to school.

Thanks!
Jerking at highway speed sure sounds like a bad Crank sensor, but not sure it would go bad in 3 years. I think mine from new took 5 years to show up.
 

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usually it's battery problem. Remove the terminals and brush the surface. Then check the engine idling, fuel injectors.
 

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I would conduct a tps check. My 2.7 developed a random drop over time. They are like $25 at the dealer and they have an "improved" design now.
 

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Discussion Starter #5
usually it's battery problem. Remove the terminals and brush the surface. Then check the engine idling, fuel injectors.
THanks camper, but how would this affect the speedometer at idle? I can see the tach, but the speedo, no.
 

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Just some more back story:

Back 3 years ago when I did a ton of work to the car getting it on the road for my daughter (timing belt, water pump, brakes, etc.), I had a hard starting problem which I tried to cure with the crank sensor so that's why I replaced it. Ended up being the fuel pressure switch so that got replaced too along with new plugs and wires. Fuel pressure test was never done as there really isn't an easy way to do it on this model.

When I noticed the jerking behavior the other day, it was on a test drive after replacing the power steering pump. But my daughter admitted experiencing it once or twice even before that.
 

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Hi. Throttle Position Sensor. They provide a linear voltage to the computer to correspond to your actual throttle setting. It uses a variable resistor to do this. It takes a 5v source and outputs millivolts to tell the computer how much fuel to send to the engine. When they developed dead spots the computer voltage could be at .340 voltage at say cruising throttle speed, then you just slightly change you throttle setting and the internal wiper arm in the tps loses contact and the signal drops to zero. The computer will then abruptly cut fuel to the engine until the wiper arm in the tps makes contact and resumes sending a signal. It feels rather abrupts at a slight load.
 
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