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Mike V.
Mike V., Subaru Technician
Category: Subaru
Satisfied Customers: 25312
Experience:  Certified Subaru Technician, factory trained by Subaru.
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I have a 95 Subaru Impreza Outback. Very rough idle and

Customer Question

I have a 95 Subaru Impreza Outback. Very rough idle and stalling out. I have replace the plugs and wires, but still the same. Any suggestions?
Submitted: 1 year ago.
Category: Subaru
Expert:  Mike V. replied 1 year ago.

Hi there,

Is the check engine light on or flashing when the engine is running?

Customer: replied 1 year ago.
No. I changed the plugs and wires today thinking that would help but it didn't.
Expert:  Mike V. replied 1 year ago.


Unplug the mass air flow sensor and see if there is any change. Sometimes these fail and don't set the light. When you unplug it, the light will come on, but try it, unplug it and then start the car and see if it will idle and run better. If it does, then the car needs a new maf. It's pretty common so let me know.

Please let me know if there is any more I can do to help you from here.

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Customer: replied 1 year ago.
I unplugged the maf this morning. The check engine light came on and the the car stalled. I went to the local parts store and purchased some maf cleaner and throttle body cleaner as well. Nope of this has helped yet. Still has a very rough idle and when you put it in gear, it acts like it's going to stall.
Expert:  Mike V. replied 1 year ago.

Did you unplug it with the car running?
You need to unplug it and then start the car. Sorry if I wasn't clear enough on that point.

How does the car run off idle? Is it drivable?

Customer: replied 1 year ago.
No that's fine....I unplugged it and then started the car. It started...the light came on and then stalled out. Yeah it's fine off idle. Goes down the highway with no problems. Do you think it may be the IAC valve? I haven't replaced the PCV yet either. I'm trying least expensive first.
Expert:  Mike V. replied 1 year ago.

Could be the IAC, but could also be a vacuum leak. Will the car idle long enough for you to spray some carb cleaner around the intake manifold. If it will, you can spray the carb cleaner and see if the idle smooths out of speeds up. You could use the maf cleaner for this as well. Just don't see the IAC fail on these often and really don't want to guess about it. Also, some of these had EGR valves. Do you know if yours does? If it's sticking open it could be causing the issue at idle.

Let me know.