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Q: RPM fluctuates, car jumps at speed decrese

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The issue with my car happens when I'm bringing the car to a halt and slowing down. Then, as the RPM is close to 1, the car would jump forward and increase the RPM. Then it would go down and get back to normal. This happens occasionally and while it lasts, I'm not accelerating. What could be the cause? Thanks.

A: This sounds like a shifting issue. The tr...

This sounds like a shifting issue.

The transmission needs to select the proper gear based on how it is adapted when you come to a stop. If the shift is delayed, then the load on the engine will momentarily drop while the transmission is between gears. This can cause an increase in RPM and then, when the gear is engaged, the vehicle has a slight jump to it. This can be from reasons from faulty programming to a lazy solenoid.

Fault codes should be read out and the latest software should be installed. This is generally a dealership fix, as they will have the proprietary software necessary to correct program levels and read solenoid statuses.

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