I have a 2006 OBW with some idling issues (very low idle at stoplights...sort of shakes and sputters) and sluggish acceleration from a stop/slow start) and then a couple of weeks ago it felt like it really wanted to stall when I put in gear and at stop lights (enough so that I didn't drive it to work). I changed the PCV valve last week and it seemed to clear some things up (better acceleration from a stop and a bit better idling). Then I noticed that the mileage was dropping considerably (roughly 5 mpg).

 

I've been doing quite a bit of reading and was going to clean the throttle body and IACV valve which both seemed easy enough but one forum I read said to make sure I have the gasket to replace on the IACV before I start. I called my dealership to get one and the guy said they don't make them for the 2006 model because the IACV was part of the throttle chamber ($575 new!!) and that trying to clean either would cause serious problems to my car. Is this true?

 

Is this something that's changed in the later model Subarus? The forum I read seemed to describe EXACTLY what my car is doing and that cleaning the throttle body and IACV seemed to clear it up for most people who did it. The guy at the dealer mentioned that it could be a vacuum leak causing the idle problem but I'm not real sure where to spray the carb cleaner to check that. He also said the major drop in MPGs could be caused by a switch over into winter mix fuel. This is the second winter I've had the car and didn't notice any change in MPGs last year.

 

Any help here would be GREATLY appreciated.

I had the same problem in my 2005 legacy, low idle, stuttering on acceleration, all i did was pull off the air intake,and used a toothbrush and a little gasoline to clean off the throttle body plate. It had lot of black soot type stuff built up around the edges. Problem solved,idles and runs perfect now.

Awesome!! So what about the guy at the dealer (parts guy, not a service guy) telling me that the IACV and throttle chamber are all one piece now and not to mess with them because I'll mess them up? Did that change from 05 to 06?

What engine and transmission do you have?

 

Sloppy idle and sluggish acceleration point more toward a vacuum leak.

 

But periodic cleaning of the intake system and throttle body will help keep things running smoothly.