Major hesitation and very strange sound at 5,000 RPM
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This is a discussion on Major hesitation and very strange sound at 5,000 RPM within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; So the past few days my car has been acting up and i can't quite seem to figure out what's ...

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    Registered User kawiman6565's Avatar
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    Major hesitation and very strange sound at 5,000 RPM

    So the past few days my car has been acting up and i can't quite seem to figure out what's causing it to do so. In first gear when I'm to the floor and the RPMs reach about 5,000 (+/- 100) the car has major hesitation and starts sounding like I've hit red-line but as soon as the revs get past about 5,500 to 5,800 RPMs it stops and acts fine until i sift. Once i get into second gear its fine and just today it did the same thing in second but not as harsh or sudden. This hesitation and almost "WOT Box" sound starts and ends at the same point in both gears (5,000) but doesn't do it in any other gears. This same thing happened to me when I was doing some fairly aggressive driving in the mud and went through a puddle, and I remedied that by changing the cone and cleaning the MAF sensor with an approved solvent. Cleaning the MAF in this case didn't help at all and was hoping someone had some insight as to what this may be.

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    Registered User kawiman6565's Avatar
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    Mods include stage 2 clutch, lightweight flywheel, TBE, lightweight crank pully, dual core radiator, short ram intake

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    Admiral Ackbar mycologist's Avatar
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    No CEL?
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    Captain James of the SS Impreza has gone down with the ship Drews's Avatar
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    Quote Originally Posted by kawiman6565 View Post
    lightweight flywheel, lightweight crank pully
    These two things can cause misfires when used in conjuction. If you have a racelite flywheel those are known to cause misfires on their own...I'd do some logging, and that will tell you what is going on. Pretty much your only option if youre not throwing a CEL.
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    Registered User kawiman6565's Avatar
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    Both those parts have been in since i purchased the car and it never had a problem, the flywheel is a 12.5lbs one I'm told and ive never had a miss-fire with the car other than a bad coilpack. At the moment I do not have any CELS but that is because i put a non-fouler in since I don't have any cats it was throwing a code for lean, rich and two other codes that were directly caused by the removal of the cats I have the exact codes written down and will post them tomorrow since they are not with me, I don't normally get on the gas hard when the car is cold but today I did to see if there was a difference and the hesitation and "redline" sound is worse when its cold and lasts from about 5,000 rpms to 6,250 rpms. Thank you for the help

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    Admiral Ackbar mycologist's Avatar
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    This isn't a real common scenario, and is really hard to guess at. It could be so many things I'd recommend having it diagnosed. Could be as easy as some seafoam and I don't want to even suggest the bad end of the spectrum.
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    Registered User kawiman6565's Avatar
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    My apologies for not replying quickly I was away from home for a few days and have talked to a friend that is very familiar with Subarus and he said the same thing, to just get it diagnosed. I'll post what the outcome of this is when I do so and again thank you all for the help!

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    Registered User tesla317's Avatar
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    A little old, but thought I'd chime in.

    My 2010 was completely stock when I got it. I quickly decided to get a typhoon K & N intake. Installed it and quickly noticed that in first and second gear I would get a lot of hesitation at 4k - 4.5k rpms. After 5k it would clear up.

    I installed the original intake, and presto!!! Problem solved. K & N says you dont need a tune....i disagree.

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    Moderator Donkey's Avatar
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    Quote Originally Posted by kawiman6565 View Post
    At the moment I do not have any CELS but that is because i put a non-fouler in since I don't have any cats it was throwing a code for lean, rich
    Removing the catalytic convertors does not cause a lean or rich code. The problem is probably the intake and no engine management. Without a datalog correctly diagnosing this over the internet is slim to none. Where exactly did you put the anti fowler?
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    Master Baiter EJ257's Avatar
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    Quote Originally Posted by Donkey
    Where exactly did you put the anti fowler?
    Hopefully locked in the cabinet with the other guns.
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    and the Funky Bunch Calvinball's Avatar
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    Quote Originally Posted by EJ257 View Post
    Hopefully locked in the cabinet with the other guns.
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    Registered User teflon_jones's Avatar
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    The intake can cause issues because of the oil on the filter getting on the MAF. The typical behavior of a fouled MAF is hesitation at about 4-5k RPM not only in Subarus but in most cars in general. It usually manifests itself at about 2/3 of redline.
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    Registered User Heide264's Avatar
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    I didn't see it anywhere, but are you tuned for the intake?

    If so, it could be a bad tune.

    It could be possible you are hitting 'fuel cut' due to an over-boost situation. Can you do any datalogging? I don't believe fuel cuts come up at CELs strange enough if you have your overboost stuff set higher.

    More than likely not, but something to look into.
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    Moderator Donkey's Avatar
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    Quote Originally Posted by EJ257 View Post
    Hopefully locked in the cabinet with the other guns.

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    I seem to have developed roughly the same issue as the OP. I have an '05 WRX with only the stock STi DP and exhaust as modifications.

    I get all the same symptoms, hesitation at half to WOT around 4-5K RPM. I did another pull recently to see if it wasn't just in my head and that time I actually heard a rattling noise coming from the engine bay. I'm going to double-check my CEL tonight to make sure it's still just the P0546 code that I've been ignoring.

    Seems like the best thing to do right now is take it in to get diagnosed from what I'm reading. I figured I'd post just in case anyone came across anything new.

    Thanks in advance!

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