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Discussion Starter #1
I'm trying to hunt down a solution for this issue. Thanks to everyone who might chime in on this.

2007 OB basic (2.5 non-turbo) MT

Recently has been loosing power, especially on hills. Timing belt, plugs, wires, and coil all were replaced less than 5k ago. I just replaced the front cat this week. Power is now worse, motor won't rev past 4k in 2nd, 3rd, 4th, but will rev freely in neutral. Runs the same with MAF plugged in or unplugged. Not throwing CEL, no codes in computer seen with a cheap OBDII scanner. Any suggestions where to look next?
 

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2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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Discussion Starter #3
197k, ran great about 3 months ago. New HG's too.

NGK plugs and a used coil pulled from running OB. I thought if the coil was going bad it wouldn't rev in neutral.
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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197k, ran great about 3 months ago. New HG's too.

NGK plugs and a used coil pulled from running OB. I thought if the coil was going bad it wouldn't rev in neutral.
does the coil you got there say "subaru" on the front. what outback was it in (model/year/ engine/trans)?
did you make sure it matched by a subaru parts site?

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it is odd it revs in neutral. this is a drive by wire car though....so odd things like this are more possible then a traditional throttle.

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edit: and I see this is a US spec car based on ip address if anyone was wondering about years/ vs. world years.
 

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Discussion Starter #5
Great suggestion on using the onboard diagnosis (which I didn't know this car has). Shows:
P0102
P0113
C0140
 

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Discussion Starter #6
Update:

Codes for MAF were because I unplugged it. I cleared the codes, test drove, now P codes are gone (no CEL or codes at all), still running like it's on 3 cylinders or getting starved for spark or fuel. Back to square 1

Coil is aftermarket, not Subaru brand.
 

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I'm trying to hunt down a solution for this issue. Thanks to everyone who might chime in on this.

2007 OB basic (2.5 non-turbo) MT

Recently has been loosing power, especially on hills. Timing belt, plugs, wires, and coil all were replaced less than 5k ago. I just replaced the front cat this week. Power is now worse, motor won't rev past 4k in 2nd, 3rd, 4th, but will rev freely in neutral. Runs the same with MAF plugged in or unplugged. Not throwing CEL, no codes in computer seen with a cheap OBDII scanner. Any suggestions where to look next?
Symptoms are not unlike a blocked or restricted catalytic converter with the possible exception of high revving in N. There's two cats on that basic 2.5. Why was the front cat replaced? If for a suspected blockage, what about the second cat?

These posts might be of interest. They're both about blocked cats.

https://www.subaruoutback.org/forum...nce/293913-07-no-power-limp-mode-no-cels.html
https://www.subaruoutback.org/forums/66-problems-maintenance/317058-07-outback-2-5-no-power.html

Note that in the first thread, the free-revving limit was 5k, not the 6+k that it should be. How high does your's rev in N?

Has the fuel pressure been checked, particularly under load?

Might also be helpful to set up Romraider and log data, as in the linked threads.
 

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Discussion Starter #8
Front cat changed because it was cracking and whistling under load. That was definitely original equipment too, so no surprise it was time to go.

Revs to above 6k in neutral. I just felt a slight stumble when I first revved it, but it went away immediately. Still no new CELs
 

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double check crank/cam timing, then, compression test might be next - If it runs the same immediately after an ECU reset, doesn't seem like an a:f sensor problem.
 

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Discussion Starter #10
Good point about how it runs after a reset. It doesn't run the same initially, it stumbles and hunts like crazy for a bit while it "gets it's bearings", then runs the same (IE low power)
 

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Discussion Starter #11
Issue resolved, thanks to all who made suggestions.

Just to follow up, I disconnected the exhaust at the rear of the front cat and went for a drive. Plugged second cat was the culprit. Weird it would rev freely in neutral though...

Now it's replaced and it's running great. I changed the front O2 already, and I plan on changing the plugs asap and maybe running Seafoam through her to help loosen the deposits that must have formed from unspent exhaust backing up into the motor. Any other things to check on that might have gotten fouled with both cats plugged?
 
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