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Old 06-01-2002, 08:59 AM   #1
Scooby Newbie
Member#: 17020
Join Date: Mar 2002
Default Help--A/C related engine stumbling

My '99 Impreza 2.2 A/C will run ok for a few minutes, then the A/C starts causing a very noticable "stumble" in the engine every 2-3 seconds while driving. I first thought it was a mis-fire, but when I turn off the A/C, the engine smooths out. This is a lot more than a normal A/C compressor just kicking on. It cycles every few seconds & feels almost as strong as tapping the brakes. I also am not getting air as cold as I would expect. I have had it recharged (of course the A/C was working "ok" in the shop at the time), but that did not improve it--So, some questions: does anyone know how many degrees colder the A/C air should be per Subaru specs?? What could be causing the A/C to put such a big, intermittent load on the engine? Is this hurting anything else on the car? How often (seconds) does the compressor cycle on/off with the A/C on high? Thanks--I'd appreciate any advice!
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Old 06-01-2002, 01:08 PM   #2
Trust no one
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
02 RAV4 MT
15 WRX/11 CRZ


It is possible the system is overcharged and is cycling via the high-pressure cutout rather than the normal controlled cycling, if this happens it will be more violent and cause a feeling of surging in then engine as it cycles every few seconds. My WRX did this after adding some extra charge because we thought it was low, after rechecking the system and letting some refrigerant back out it is now ok.
R134 systems are very sensitive to pressure variations so you may need to have it checked again.
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Old 06-10-2002, 11:11 PM   #3
Scooby Newbie
Member#: 17020
Join Date: Mar 2002

Mulder- Thanks for the info! IJ'll give it a shot w/ the shop.
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Old 06-11-2002, 12:11 AM   #4
Dolphin Overton
Scooby Specialist
Member#: 1925
Join Date: Jul 2000
Chapter/Region: RMIC
Location: denver
01 A4 89 944s2
13 Speed 3R 99 Sprint


I am about to get mine fixed for the same problem(under warranty) there is a valve of some sort that is getting stuck... or that's what they told me anyway. When they fix it I am ripping the A/C out and selling it
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