Subaru Outback rough idle
My 2013 Subaru Outback has developed a rough idle issue. It started as a very small shudder when coming to a stop but over time has lasted longer and longer during idle. It doesnt happen all the time. And not while in park. Additonal electrical load makes it worse (power windows, blasting A/C, etc.). I have cleaned the MAF, changed the filters and relearned the Idle. Anybody have suggestions?
Disconnected/broken vacuum lines can cause this, might check to make sure rotors aren't warped, might also try cleaning idle air control valve and throttle body
How many miles on the car? Maybe it is time for new spark plugs.
I have cleaned the MAF and throttle body with no results. Gonna give spark pluga and a can of seafoam a try and see how it goes.
The shudder could be a failing CVT or the torque converter which may be covered under an extended warranty.
Ta dah! FOR's a great student, as it is indeed likely that a new valve body is needed in your CVT because of an intermittent solenoid. See SOA for a freebie.
I had the cvt checked out by a subaru dealership when this issue first started and they didnt find anything wrong there.
Is it acting like a lean gas mixture or rich gas mix? I wonder if the air fuel ratio sensor is wearing out. Unfortunately I'm not sure how to test it
"...Gonna give spark plugs and a can of seafoam a try and see how it goes." Did this resolve this issue?
Seafoam and spark plugs did not seem to fix the issue. Though the spark plugs were pretty gunky. Found a very small amount of oil in one but not enough to drown it
Since the additional electrical load makes it worse, check the battery, a weak car battery can lead to slower processing of the fuel pump which can lead to “lean fuel”. Also, a weak battery can cause the improper opening of certain injectors. All these conditions together can cause misfiring of the engine. It's an easy fix and simple to test.
