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Old 09-04-2012, 11:41 PM   #1
dhm8484
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Default Car hesitates when building boost help

So here's the deal. My car has been doing this for some time not whole time w I was stage 2, it is stage 2 cobb, and cobb sf intake with 3 inch exhaust and catted dp, when you are in every gear but first, when you are cruising around and the car hesitates when rpms are between 3-4500 rpms, and boost gauge is starting to 0 and up to .5, then if you press gas down whole way it builds boost fine up to 1.1 and doesn't fluctuate holds steady has Subaru factory gauge, the accessport a/f will read up to 18 to 19 when it hesitating and acting up. I saw my turbo inlet was ripped so I changed it with a gimmick, and cleaned maf, plugs have been changed too (when clutch was changed started doing it after this trip to garage) and it still didn't help it. So I'm lost not sure if it's a leak somewhere or not I'm lost. It's an 03 wrx with 83k on it. Anyone have ideas I'd like to know cause I'm out of them. Thanks in advance
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Old 09-05-2012, 09:51 AM   #2
dhm8484
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Wanted to add that it started doing it before clutch and plugs, and it's worse with the ac on. The motor isn't making any noises just feels like it's going in and out of boost but gauge doesn't move.
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Old 09-05-2012, 10:51 AM   #3
tebriel
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i would suspect you're running lean. lol.

You'll need to datalog to see what's going on.
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Old 09-05-2012, 05:51 PM   #4
dhm8484
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Yea it's running lean when messing up but the stops in upper rpm range. Just that certain rpm range it does it.
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Old 09-06-2012, 06:23 PM   #5
dhm8484
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Does anyone else have any other ideas off top of there head?
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Old 09-06-2012, 08:04 PM   #6
brew02wrx
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We need data logs or else we can't help you

If you can't provide those for whatever reason then go to a tuner and have him log your car


If it were me id go with option b
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Old 09-08-2012, 07:25 AM   #7
jaxscuby
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torn inlet hose..unmetered air running lean..

not good..get a new inlet asap.

before you have to replace the motor.
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Old 09-12-2012, 10:33 AM   #8
dhm8484
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I already replaced the inlet hose because the old one was ripped around hose clamp on turbo, same thing I even switched back to the stock map to see if it was the Cobb map doing it and it did the same thing (only did this for a short drive and didn't even get on it) so I switched back. I never logged anything before so I'll hive that a try.
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Old 09-13-2012, 01:29 PM   #9
dhm8484
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So I went over every sing hose clamp that I could tighten under the hood, and found that the bypass valve hose going to it was a little loose got maybe half of turn out of it. Could this be the plugs or maf? At idle my boost gauge reads between -.5 and -.6 and one you are moving you hold clutch in it drops to -.8 this normal?
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Old 09-13-2012, 06:19 PM   #10
dhm8484
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Anyone I'm lost
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Old 09-13-2012, 06:24 PM   #11
brew02wrx
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I already told you what to do to get some actual help
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Old 09-13-2012, 07:19 PM   #12
dhm8484
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Yea well that's why I post on here my computer is down so I can't log anything off of the AP, if it's something I could do then I'm going to do it. I'm not a noob when it comes to cars, having built and driven a Honda that would beat a lot of cars on here (25 psi at 436 hp running mid tens) this is my first Subaru and it's all learning and this has me stumped. Likes I said not the car is um drivable and bucks you back and forth in the seat, it's more annoying than anything. I'm just looking for ideas in the mean time till I can log what I already have and put it on here.
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Old 09-13-2012, 07:36 PM   #13
brew02wrx
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Ok I have 1 question for you, what cobb map are you running?
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Old 09-13-2012, 08:05 PM   #14
dhm8484
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I'm running the Cobb stage 2 that's the 92 oct.
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Old 09-13-2012, 08:29 PM   #15
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I meant 91, even tried the Nevada crappy gas one which didn't help, I'm not having trouble reaching target boost levels it's around 16 psi
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Old 09-13-2012, 08:34 PM   #16
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Contact Cobb or find a way to data log for us to help.. thats all folks
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Old 09-13-2012, 09:29 PM   #17
brew02wrx
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Quote:
Originally Posted by dhm8484
I meant 91, even tried the Nevada crappy gas one which didn't help, I'm not having trouble reaching target boost levels it's around 16 psi
So you aren't running the map that's made for the cobb intake I take it?
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Old 09-19-2012, 06:32 PM   #18
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Yes I'm running the Cobb intake with the Cobb maps, it says stock or Cobb sf intake under map description
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Old 09-20-2012, 11:51 AM   #19
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You could have damaged your maf when you cleaned it. What did you clean it with exactly? Also, could be a front o2 sensor. Or fuel filter or something else fuel related. Go to a shop, have them smoke test your intake and also check for boost leaks. Get it smoke tested first, if there is a post intake Tract leak, well fix it. If its fine, did someone with a maf sensor, switch them out reset your Ecu and run a tank of gas. Check your age readings. They should be +/- 5%
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Old 09-20-2012, 04:38 PM   #20
dhm8484
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I cleaned it if electrical cleaner spray, I changed the fuel filter a year ago, if the o2 sensor is going out would it throw a code, and a ever changed the maf since I have had the car, and the problem hasn't always been there since going stage 2 it was a developing problem, I would log with access port but it is frozen and needs to be sent back to Cobb so they can fix it and update it.
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Old 09-20-2012, 04:53 PM   #21
conklin_02
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Well it sounds like you need to bring it a tuner than. Send your accessport back ASAP. There would only be a code if the o2 sensor was completely dead. Same with the maf. They can both become worse and worse which makes your car run crappy. Without logs though, it makes it really hard I suspect what the problem is
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Old 09-24-2012, 10:08 AM   #22
atxbugeye
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I had the same problem for 6th months before figuring out the problem. I too had a ripped turbo inlet, PITA to replace by the way. I ended up having a weak coil pack. Only sputter at WOT under boost and it would cut out like a fuel cut or something. I had NO CEL ever. Turns out I had a bad ignition coil! I didn't know which one so I just replaced one, drove it still was cutting out, then swapped it with the next one and bam! It was fixed! My problem started about six months ago after hauling ass going on the freeway, then it started cutting out. I'm almost positive it is a bad coil!
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Old 09-24-2012, 03:53 PM   #23
oOIIJoshIIOo
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I've been having sorta the same problem. 02 WRX 130k. I replaced my A/C compressor and put a new belt on (which there wasn't one before I got the car) and it started this really bad missing. I changed the plugs and I ran fine for about a week and now it is doing it again. WOT from about 4-5500 RPM. Changed fuel filter and that didn't help. Only code is P0103 or MAF. I'm just as stumped as you.
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Old 09-27-2012, 06:12 PM   #24
oOIIJoshIIOo
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Starts at around 4-4500 RPMS and continues from there. Only does it usually at WOT.
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Old 09-24-2012, 07:33 PM   #25
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^^ so you have a maf sensor cel?
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