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idle drop on decel with A/C on.


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I don't run with the AC Auto system on much during the winter as the extra pull of the compressor makes the clutch feel heavier plus it lowers the temp of the interior a couple of degrees in the coldest winter days. nothing big or concerning, just the way i like it.

Since we've had much rain (instead of snow) lately I've been needing the defrost and thus AC system.

I've noted when I take the car out of gear while decelerating and the RPM head toward idle if the AC system is "on" then the idle will drop 200-300 RPM below idel for a sec or two before finding the right spot. Doesn't do this on decel with the AC compressor disengaged?

Any ideas what causes this?

Does this occur on your car?

Shawn

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I have a 1997 but I only turn the a/c on a few times a year just to make sure it still works.

At idle when I turn it on the rpm dips then recovers. There was a remap years ago to prevent stalling. Peter did it for me about 5 years ago, but he said it was really only for 1999s. I noticed no difference after this remap.

I have not paid attention to the a/c when I'm on and off the gas.

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I have a 1997 but I only turn the a/c on a few times a year just to make sure it still works.

At idle when I turn it on the rpm dips then recovers. There was a remap years ago to prevent stalling. Peter did it for me about 5 years ago, but he said it was really only for 1999s. I noticed no difference after this remap.

I have not paid attention to the a/c when I'm on and off the gas.

Thanks. I actually have the opposite whe the AC is turned on. It shoots up to 1100rpm then comes back to 800rpm and all is fine. Although the drop when decel doesn't cause a stall I figured it would increase until this eventually happens. Had this issue on a Vw Vanagon with AC that progressivly got worse.

Still hope to hear from others who have lived with for years or not.

Shawn

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  • 2 weeks later...
my 97 does this as well. i'm not exactly sure why, but i always figured it was the a/c 'kicking in' (cycling on).

yea but why would it "cycle on" everytime it decels? the unit only kicks off under hard driving (i believe over 4500RPM or such).

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my 97 does this as well. i'm not exactly sure why, but i always figured it was the a/c 'kicking in' (cycling on).

yea but why would it "cycle on" everytime it decels? the unit only kicks off under hard driving (i believe over 4500RPM or such).

maybe you just don't notice it when you are accelerating as there is enough power being generated that it doesn't cause a significant power draw when it cycles on? just thinking out loud...

but this does happen to me, and only when i slow to a complete stop (or almost a complete stop.) the car never stalls, the RPMs just dip down for a second and then come back up. doesn't happen when the a/c is off.

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