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My 2003 CTS vibrates pretty bad at idle speed (around 600 RPMs) But If I rev up to 800 or so, it's totally smooth.

The real problem is partially due to worn motor mounts, but I dont want to spend $500 to replace them right now.

So, is there any way for me to reprogram the idle speed? Would I have to purchase some aftermarket chip?

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up vote 3 down vote accepted

Aftermarket tuners/PCM flashers (such as HP Tuners) will allow you to do this. However, HP Tuners costs about $600, so your best bet would be to find a friend or shop who already has one, unless you see yourself using such a tool often.

Also, worn motor mounts will put more stress on other mounts in the driveline (transmission, rear diff, etc.) so it might be smarter to just change the mounts.

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On some vehicles the Throttle Position Sensor can be adjusted. You can loosen the screws and gently move the TPS until the idle speed changes. I do not recommend doing this.

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Your recommendation is a good recommendation. Don't do this unless you really know the ramifications. – Pᴀᴜʟsᴛᴇʀ2 Jul 23 '15 at 16:26

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