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Registered
2004 Outback Wagon 4 cylinder
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4 Posts
Discussion Starter #1
Hi All:

thanks for being here; these forums are always remarkably helpful.

Problem: no soft or easy lift-off of throttle in our 2004 4 cylinder Outback. Engine runs fine in every respect except when you go to ease off the throttle and then you can't - it's as though you simply stepped off the clutch in a downshift or something. Wham, instant full back pressure braking and everyone in car lurches forward.

Local mechanic says is "normal with these cars" but no way. We had a day or two where on its own it resolved but then it returned and we've just been living with it (ginger, tender right foot).

I figure some kind of vacuum line, something blocked, or bad sensor? Something is being told to clamp down but it is NOT normal.

Ideas?

thanks,

Henry
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
Could be a sticky throttle cable, you let off the pedal, it keeps a tiny bit of throttle on, then a split second later releases it suddenly.

Same mechanism but could be sticky throttle plates.

Could be the throttle position sensor, maybe a dirty idle-air controller (IAC)?
 

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Registered
2004 Outback Wagon 4 cylinder
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4 Posts
Discussion Starter #5
What about the IACV?

Thanks for the responses.

How about something bad with the Idle Air Control Valve? When I try to ease off the gas pedal, it just feels like the intake shuts completely rather than allowing at least some air to pass through, hence the engine-brake feeling.

Found this link that sounded on point. What do you guys think?

Henry
 

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Premium Member
03 H6 OBW & 06 WRX Sportwagon
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18,130 Posts
henry - maybe post up your city, and someone may be able to suggest a shop you could take the car to and have them test drive/check it out.
 

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2004 Outback Wagon 4 cylinder
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4 Posts
Discussion Starter #7
Am in Potomac, Maryland

Thanks Texan and Sorry CNY Dave - duh, you listed the IAC in your post.

Am checking out your sticky cable; that was a good intuition in terms of what's the SIMPLEST thing that could cause this issue. They want a lot of $$ for a new IAC...
 

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2004 Outback Wagon 4 cylinder
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4 Posts
Discussion Starter #9
You were right! Problem fixed!

Sorry it took me so long but my son went back to college with the car and didn't want me to work on (disable) it until he didn't need it anymore.

It was a dirty IACV afterall and all it took was some carb cleaner and a few Q-tips. Throttle lift-off problem solved.

This was especially satisfying because my very good and usually reliable mechanic had just sort of brushed off the problem with a "normal for these cars" comment. Not good enough for me. We LOVE this car and the throttle behavior simply was not right.

All fixed. Thank you guys for your feedback and solution. Pat yourselves on the back.

Henry
 

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1993 Legacy LSi with still functioning Air Suspension, 1999 Outback 2.5L 5MT lab Rat
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191 Posts
Depends on the 2004, PZEV 2004's are Throttle by wire, they also have a different torque braking and exhaust system. The PZEV also has a single TGV plenum which under some circumstances could inhibit intake airflow. If this is the case its likely an electrical problem since there are no vacuum controls for the TGV or ETC.
 
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