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Old 07-10-2013, 09:31 PM   #1
BeardedShogun
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Default stock 07 wrx, cylindar misfire, hesitation at wot

Would love some help for this situation, can't seem to figure out what's the problem.


my WRX is bone stock, no performance mods yet at all.

some problems I'm seeing is:

hesitation at WOT, will hold at 4-5k, take off, and hold again.
a possible overboost
CEL flashing, cylinder 3 misfire.

Running only 93 octane and have used fuel cleaner regularly to try to eliminate an injector problem.
what could it be?
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Old 07-11-2013, 08:39 AM   #2
Dr. octagon
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Quote:
Originally Posted by BeardedShogun View Post
Would love some help for this situation, can't seem to figure out what's the problem.


my WRX is bone stock, no performance mods yet at all.

some problems I'm seeing is:

hesitation at WOT, will hold at 4-5k, take off, and hold again.
a possible overboost
CEL flashing, cylinder 3 misfire.

Running only 93 octane and have used fuel cleaner regularly to try to eliminate an injector problem.
what could it be?

Seems as though its misfiring, seems you have identified the missing cylinder. Search misfire, and stop using that fuel injector ****. If the injectors are dirty, pull them and send them off to get cleaned.
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Old 07-15-2013, 09:46 PM   #3
diablo0730
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Clean the MAF i had the same problem and MAF was dirty as heck.
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Old 07-17-2013, 12:53 AM   #4
BeardedShogun
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Quote:
Originally Posted by diablo0730 View Post
Clean the MAF i had the same problem and MAF was dirty as heck.
did that

probably going to buy a new one.


Cleaned the boost solenoid as well, no change.
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Old 07-18-2013, 01:47 AM   #5
Mukeworx
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I'm having the same issue... Did compression test, leak down, all good, new plugs and coilpacks still cylinder 4 misfire....
Clogged injector??
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Old 07-18-2013, 09:34 AM   #6
kungfuturkey
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This could be the starting signs of a coil going out... My car did this when I first bought it if I was on the hwy for a long period of time always the same cylinder. A year later the coil went out all the way...
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Old 07-18-2013, 12:23 PM   #7
SlimJim8804
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Quote:
Originally Posted by kungfuturkey View Post
This could be the starting signs of a coil going out... My car did this when I first bought it if I was on the hwy for a long period of time always the same cylinder. A year later the coil went out all the way...
Said coilpacks were new.
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Old 07-19-2013, 01:45 AM   #8
street carp
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Check all the vacuum lines. Better yet, get a smoke test done at the shop. A vacuum leak could cause a misfire.
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Old 07-19-2013, 02:15 AM   #9
BURNING4ORCE
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From my experience if it's a injector problem, not always, the engine idles really rough. Try swapping out coil packs to the next cylinder see if the misfire follows the cylinder it was swapped too. Since it's the 3rd cylinder( top passenger side) swap below the 1st which is located in the bottom towards the radiator. Change plugs too if that hasn't already been done. It could be numerous thing, vacuum leak, o-ring from injectors, wiring, fuel rail lifting up only at wot at certain boost pressure, best thing to do is to get a smoke test done like someone already mentioned and if that passes a cylinder leak test to see if that cylinder or motor is healthy. If you have someone with a tactrix cable locally you even log your car to see where it's at and maybe see if it has a leak or not.
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Old 07-19-2013, 06:03 AM   #10
BeardedShogun
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Thanks for the suggestions, I replaced the plugs and my cylinder misfire cel went away.


However my other problem still occurs. hesitation and bucking at wot, car gets to about 5k (sluggishly) and just hits a wall.


I'm definitely going to take some suggestions from here, but could this be a possible overboosting problem?
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Old 07-19-2013, 06:17 AM   #11
BURNING4ORCE
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Do you have a boost gauge? It could be overboosting as it seems like your hitting fuel cut, have you thrown any codes for overboosting like p0244 or so? Run wastegate boost pressure by connecting just 1 single hose to the wastegate nipple and to the turbo compressor nipple where your turbo is and do a wot pull again if hesitation is still there then we can rule that out to some extent. Quit doing those wot pulls for the meantime to avoid any possible catastrophic failure. Check for leaking/cracked boost lines or loose lines on the turbo hoses as well.
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Old 07-19-2013, 03:20 PM   #12
BeardedShogun
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No, haven't thrown any turbo specific codes, closest would be a "system too lean" code that went away shortly.

All the lines look good to me, I'm about to just bite the bullet and take it to a mechanic.
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Old 07-20-2013, 04:48 AM   #13
kungfuturkey
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Quote:
Originally Posted by SlimJim8804 View Post
Said coilpacks were new.
Sorry I missed that. Have you checked fuel pressure? Your fuel pump could be on it's way out it takes a while some times and can be pretty subtle.
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