samert111 Posted November 4, 2017 Share Posted November 4, 2017 Working on a 2005 Legacy GT, 2.5L Turbo and at cold start up it idles great at around 1500 RPM for about 30 seconds then as soon as it tried to idle down it's like a switch is thrown and it starts to idle rough and will also stall sometimes. Each restart once it's warmed up the idle is rough but let it cool completely and the cycle starts all over. It's obvious it's running too rich once it starts to stumble. Car runs great while driving it as long as you keep the RPM's up. The PO removed the Cat and replaced it with a wrapped down pipe from the turbo. The O2 sensors appear to be operating correctly per my scan tool. I'm also getting misc cylinder misfires on all cylinders which make sense because it's over fueling. The MAP sensor seems to be working and showing different readings at various stages of throttle application. When I connect my vacuum pump to the MAP to raise and lower the vacuum applied to it at idle it doesn't affect the idle condition at all so I'm not sure what to make of it. Maybe we have a bad ECU. I've cleaned the throttle body which wasn't too dirty at all and looked all over for a loose or damaged vacuum hose. I've pretty much drowned the intake manifold and all vacuum hose connections with carb cleaner and I'm not getting any fluctuation in idle at all so I think all the hoses are intact. I'm stumped and any suggestions would be appreciated . Link to comment Share on other sites More sharing options...
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