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Discussion Starter #1 (Edited)
ABOUT* I have an 03 wrx. I am hitting only about .04 bars through 1,2,3 gear and only hit .05 like 75 80mph in 4th sometimes 5th. could I possibly have vacuum leak? things of that nature or is this typical for a completely stock wrx?
 

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I'm thinking you meant MPa, not bar. The standard Subaru boost guage reads in MPa, or megapascal, rather than bar. Just for future reference, 1 bar = 100 kPa, or kilopascals. 1000 kPa = 1 MPa, which means that .1 MPA = 1 bar.

If you're only hitting .05 MPa, that's just over 7 psi, which is standard wastegate spring pressure. So, your boost control system isn't working correctly. This could be due to a bad boost controller, disconnected vaccuum lines, or cracked vaccuum lines.

I'd suggest you inspect the vaccuum lines first.
 

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Discussion Starter #3
Yea I meant mpa my bad! I bought it from a Subaru mechanic of 27 years! He just rebuilt the motor and put everything back to stock! You think he might have just adjusted it a little lower? Idk. Thanks for the reply!
 

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He may have hooked things up incorrectly.

Here is a picture of how the standard Subaru boost control system is supposed to be hooked up, make sure you check for that restrictor pill:

 

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Helpful pic, Cody...hadn't see that one!
 

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Discussion Starter #7
Yea thanks for the pic and your help! looked at it the other day and everything looks fine!
 

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Can a bad o2 sensor cause ECU to lower the boost ?
I have a check engine (Front o2 sensor, and uppipe sensor is not installed since i have catles uppipe). I think i have the same issue with boost 0.5 Mpa at most.
 

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^^^Yes that could cause an issue. Not having an o2 sensor throws the CEL, causing the ECU to run in "limp" mode where it reduces boost.
 
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