Q: Prominent vibration throughout van when AC is on

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My wife's minivan AC blows cold, but the engine vibrates all the way through the steering wheel when it is on, and OCCASIONALLY will vibrate even if the AC is off, though very seldom, and will go away if I cycle the engine on and off a few times. So 99% of the time, it runs perfectly smooth as long as the AC is off. When it is vibrating, there is a slight drop in power. The entire time we've had the van (about 2 years) the AC is always on because the van will blow hot air through the floor vent on the passenger side where the air filter is located if we turn the AC off. Since this problem started, I went ahead and removed the fuse to avoid the whole problem.

My car has 160000 miles.
My car has an automatic transmission.

A: Hello. The heat issue that you have with th...

Hello. The heat issue that you have with the van sounds like you have a blend door issue under the dash. As for the vibration I usually check to see if the idle is getting too low when the AC is on. If it is then I start by cleaning the throttle body. Most of the time that is all that it takes to get the vehicle to run smooth again. If the idle is fine then then I check the engine mounts as that is the most common part to fail and cause this. A bad engine mount will allow the engine to move just enough when it is under load to cause it to vibrate like this. If you need to have this idle vibration checked, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.

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