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Q: Rough idling, hard shifting and shuddering at the highway

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I bought a previously owned car, which has some issues both while idling and driving. When the vehicle is not moving, like at the traffic light, it idles very roughly. Also, it is very hard to shift gears while I'm driving on the highway. The hard shifting is accompanied with shuddering and chirping sounds. What should I do?

A: Thanks for writing in about your 2002 Isuzu...

Thanks for writing in about your 2002 Isuzu Trooper. The rough idle may be due to the fuel injection system being dirty or having an engine vacuum leak causing a lean condition. The hard shifting and shuttering with the chirping sounds like you have an automatic transmission lock up converter problem and should have the transmission checked. I recommend having a transmission expert inspect your rough idling and hard shifting issue in order to make the correct repairs for this scenario.

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