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Discussion Starter · #1 ·
The car hadn't even been running maybe 5 minutes. We were sitting at a stop light and it felt like the engine rev'd while we were sitting there. Hubby didn't have his foot on the gas at all. It was enough of a difference that I felt it with my feet but hubby didn't.

There was one time that it happened again but it happened when Eric turned the a/c from level 2 to level 1. I saw it happen on the RPM meter and I turned the a/c back to level 2 and turned it back down to level 1 to see if the RPM's would go up or down when the a/c level was changed.

Is it normal for the RPM's to rise or fall when the air levels are changed?

What could we possibly be looking at?

We've already put like $2500 into this car since we bought it in Feb 2006. I hope we won't have to keep spending money on repairs.
 

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Discussion Starter · #2 ·
I know its still early but bump. I'm afraid hubby will get stranded somewhere because the RPM's will dip too low and cause the car to stall out and it be so bad that he can't get it started again.
 

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The AC compressor is powered by the motor. When it is turned on, the new drag on the motor must be compensated for. This means that the idle will go up when the compressor clutch is kicked in.

It's perfectly normal, hubby will be ok [thumb]
 

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Just in case you were wondering, the compressor clutch does not keep the compressor engaged 100% of the time. It kicks on and off depending on the pressure in the AC system, and your foot pressure on the gas pedal. If you floor the car with the AC on, the computer cuts power to the compressor clutch so that the compressor is not spinning at high rpm, and you don't have the compressor dragging on your power while you're accelerating.
 

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Just as was mentioned before, it is normal for the engine speed to fluctuate with the AC on. On my car the idle only starts moving when i move the switch to the "3" position
 

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yeah well if it was the time you were sitting at the stop light, the electric fan on the rad could turn on and *possibly* draw more current, and the engine would need to make a little more juice? just a guess...the cars i owned before this one all had mechanical fans.
 
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