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2004 WRX Power Loss? Please help...

6K views 18 replies 5 participants last post by  Sh4d0w 
#1 ·
Hello all,

I'm new to the forum and I apologize imf this question has already been answered, but I'm kinda stressed out about my new wrx.

I'm not a mechanic by any means, so please take it easy on me : /

I just purchased a wrx that I thought was in excellent shape off of a school teacher hours away from my home, on the drive home I noticed that it ran excellent, however when it was really stepped on at highway speeds the engine would almost give out for a second, and then pick back up to where it was, and kept repeating the process until I let off the gas. The first time it did the the check engine light also came on, and has been on since.

The car does not do this unless it's put under strain (not like redlining strain) and runs great for normal driving situations.

Could this be caused by the use of 87 octane fuel? Or is it a bad fuel pump or something along those lines?

I do know that the previous owner used 87 octane mores than premium, but hardly drove the car, and when they did usually didn't drive it over 3k.

What steps should i take? I added octane boost to the engine, as well as fuel injector cleaner, and about a quarter of a tank of 91 octane gas, but it doesn't seem to be helping any, and I'm down to about a quarter of a tank left.

If anyone has any suggestions, please let me know, I'd like to be reassured my new car isn't completely screwed...
 
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#2 ·
You're describing what could be severe misfire issues, or more likely boost oscillation, which can be caused by a number of things.

Was the car ever modified? If so, what was done to it?

87 octane should never be run in the car unless it's an emergency and you need to limp somewhere. It does not have enough detonation resistance for a turbocharged engine. It could be that the gas is preigniting causing detonation which can cause engine damage, but that doesn't seem like it's the probable thing.

I would take it to a trusted mechanic for a good once over. Get the plugs changed, the fuel filter replaced, air filter, engine oil and filter and maybe even a coolant flush.

Do you have maintenance records of what has and has not been done? How many miles are on the vehicle?
 
#5 ·
The car isn't heavily modified by any means, and I may take your advice on the once over, couldn't hurt anything anyways (besides my wallet). I also don't have maintenance records, though the person said they have never had any major issues with the car that needed to be fixed, and it has regular oil changes, etc.
 
#4 ·
So is it now a "permanent" problem, or a problem that after a tank or two of 91 octane it'll come out of?

I just filled it up this morning when there was about 1/4 of a tank of the "treated" 87 octane gas in it, and it still seemed to have the same issue, but I probably just hadn't given it enough time?
 
#14 ·
ok, guys I would like to know what gas should I be putting on my WRX, cause now I'm a little confused. To tell you the truth I've been using premium from Bp, so for that octane thing i really don't know what number. BTW if I've been putting the wrong gas type I'll change it quickly since I'm replacing the fuel filter and changing the oil sometime this week.



THanks everyone in advance .. . guys I'm really new at this. first car.
 
#15 · (Edited)
ok, guys I would like to know what gas should I be putting on my WRX, cause now I'm a little confused. To tell you the truth I've been using premium from Bp, so for that octane thing i really don't know what number. BTW if I've been putting the wrong gas type I'll change it quickly since I'm replacing the fuel filter and changing the oil sometime this week.



THanks everyone in advance .. . guys I'm really new at this. first car.
Seriously? There should be numbers right on the pump. Also the highest pricest gasoline has the highest octane as well. You need to use 93 if available and if not 91."Premium" is generally 89 and "Super/Ultimate" is generally 91/93.
 
#17 ·
Ok so, we have an update. I finally went to bite the bullet and took the car to the Subaru dealership. $85 and 20 minutes later they told me the valve for the turbo needs to be replaced, and that should solve my problem.

Does this sound like a reasonable fix? I'd like to hear the opinions from you guys before I go spending $300 to get it fixed.
 
#18 ·
What "valve"? There is the wastegate actuator and the boost control solenoid. My guess is the car just needs to be tuned for the exhaust. A free flowing exhaust will allow the turbo to hit the boost cut.
 
#19 ·
Ok so I got the wastegate actuator replaced. Didn't do ****. Now they are telling me the turbo is bad. I don't believe it myself.

Where would I take the car to get it tuned to allow the exhaust? Like I said I'm new to the car, is this something that someplace in my state can even do? How expensive is it?

I'm from Maine, and I'm a college student, any advice is appreciated.
 
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