Quest Posted December 15, 2008 Share Posted December 15, 2008 I have a 1997 Subaru Outback automatic with the 2.5 engine. I don't think the following is a problem, but it does have me curious. If the heater is on defrost, the engine is almost at 1800 rpms, and the car is just about to shift to 2nd, but I brake, instead of going to its normal 750 rpm idle, the rpms will go to 1000, back to 1200 for 2 seconds and then resume a normal idle speed of around 750. This makes the engine race slightly, pushing against the brakes. The interesting thing is that I can reproduce this by hitting the brake just at the right time when the defrost is on. I'm assuming the air conditioner compressor might cause an adjustment to the idle speed, and that there is just a challenge adjusting fast enough when the scenario above is present, but I want to make sure this is not a sign of something that should be looked into? Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted December 15, 2008 Share Posted December 15, 2008 You're right in that the air conditioner is involved. Something is up with the idle speed control. It could be a sticking idle air control valve or something else. But yeah that's what is happening.....the idle speed control is not working the way it should. Quote Link to comment Share on other sites More sharing options...
subaru360 Posted December 15, 2008 Share Posted December 15, 2008 I would clean out the idle air control valve, they get carboned up and stick. Unhook the battery to reset the ecu after it's cleaned out. Quote Link to comment Share on other sites More sharing options...
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