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Q: My rpm needle moves down a little then up when im at a red light.

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Hello when I'm at a red light for more than 45 seconds my rpm needle starts moving down a little then up and my steering wheel starts to vibrate a little. I changed spark plugs and ignition coils but that didn't solve it. NO hose leaks or check engine light. I was wondering if Its my throttle body or idle control valve or possibly something else? Maybe fuel filter or transmission filter?

My car has 51000 miles.
My car has an automatic transmission.

Many early 2000’s Jaguars, including the X-Type and X-Type (R) had issues with faulty O2 sensors, air fuel sensors, and ignition sensors that would cause similar symptoms to what you’re experiencing. However, an idle control valve that is dirty could also cause RPM to lower after frequent idle time as well.

A good bet would be to contact a local ASE certified mechanic and ask them to complete a diagnostic scan of your idling issue. This should give them an error code that they can trace the source of the ignition problem you are experiencing.

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