Light Throttle Stumbling
Just an update:
I noticed some weird exhaust cam phasing activity in some logs I did. During constant speed/throttle at lower RPM (say ~2K RPM), the exhaust cam would unphase either slowly or quickly (perhaps 20 degrees or so) and then suddenly jump back up to a higher phasing setting (while the intake cam wasn't doing this). I also verified it through the RPD (I am rarely on that page). I found that the stumbling occurred during the same times that this unphasing was happening.
I went to the dealer and bought new phaser solenoids (the phaser oil flow control solenoids that go in the top of the head, not the phasers themselves, that go on the end of the cams), installed them, and the unphasing and stumbling problem went away. They were the original ones since my car was new and I have almost 80K miles of use on them now, so I decided to just get both of them.
I never had any codes get thrown for the phasers. It would've made troubleshooting much easier.
I noticed some weird exhaust cam phasing activity in some logs I did. During constant speed/throttle at lower RPM (say ~2K RPM), the exhaust cam would unphase either slowly or quickly (perhaps 20 degrees or so) and then suddenly jump back up to a higher phasing setting (while the intake cam wasn't doing this). I also verified it through the RPD (I am rarely on that page). I found that the stumbling occurred during the same times that this unphasing was happening.
I went to the dealer and bought new phaser solenoids (the phaser oil flow control solenoids that go in the top of the head, not the phasers themselves, that go on the end of the cams), installed them, and the unphasing and stumbling problem went away. They were the original ones since my car was new and I have almost 80K miles of use on them now, so I decided to just get both of them.
I never had any codes get thrown for the phasers. It would've made troubleshooting much easier.
Are those the two things in the valve cover next to cyl#1?
Senior Member
Joined: 04-27-13
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From: Arizona
same thing that's happening to my '08 TC(stage2) right now, don't now what to do...gone to the dealership few times,change the fuel injector, sensors..they can't seem to pin point the problem..now it's worse, stalled me on second gear..doing this crazy sound like "Toooododododo",,scary..need help?
here is what I did to fix this exact problem. well first I changed my entire evap system. not just for that issue but for another as well. it helped quite a bit, but I still had the stumble. then I got rid of trifecta tune and got hptuners and got terminator2 to tune me. stumble totally gone.
to check it its something else in ur evap system. unplug the front solenoid on the manifold, also unplug the evap line that goes into the solenoid. drive around for a day or so and see if it fixes it, if it does, ur vent solenoid on the canister may need replacing. I also replaced the fuel tank pressure sender on the canister. plus the canister. lol it fixed my refueling issue.
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Joined: 04-21-09
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From: SoCal
Not to necropost, buuuut... has anyone who had this issue conclusively found a solution?
I've been experiencing this same exact problem lately. She does a slight stumble as if I ever-so-briefly took my foot off the accelerator for a split second.
She's bone stock and has had no mods, ever. Doesn't happen too frequently, but often enough to be annoying. Happens only during light to moderate acceleration between -10 and 0 boost. No codes, idles fine, and no misfire-like behavior. Runs perfectly otherwise.
I've ordered a set of the phaser solenoids since they're a cheap enough thing to try. Will install this week and report back.
Interesting. Has the problem stayed resolved since you did this? I've noticed some new and ominous rattles when going over the occasional bump and it sounds like suspension. Happens most in cold weather.
Guess I'll find out for myself. My car has about 127k on it and the suspension has been untouched in all that time, so I figure some preventative maintenance (and maybe some upgrades) isn't an unreasonable thing to do. If it gets rid of the stumble problem as well, all the better.
Will report back as to if this solves my problem.
I've been experiencing this same exact problem lately. She does a slight stumble as if I ever-so-briefly took my foot off the accelerator for a split second.
She's bone stock and has had no mods, ever. Doesn't happen too frequently, but often enough to be annoying. Happens only during light to moderate acceleration between -10 and 0 boost. No codes, idles fine, and no misfire-like behavior. Runs perfectly otherwise.
I've ordered a set of the phaser solenoids since they're a cheap enough thing to try. Will install this week and report back.
I had started getting some rattles when going over small bumps, and after some inspection I found that the passenger suspension spring had relaxed a bit and the rear control arm bushing bolt seemed a bit loose when I checked them. I tightened up and preloaded the coilover springs 5mm, and re-tightened the rear CAB bolts to spec, and not only have the rattles gone away, but the spark timing jumping / car bucking has also.
Guess I'll find out for myself. My car has about 127k on it and the suspension has been untouched in all that time, so I figure some preventative maintenance (and maybe some upgrades) isn't an unreasonable thing to do. If it gets rid of the stumble problem as well, all the better.
Will report back as to if this solves my problem.
Last edited by XStylus; Jan 2, 2017 at 02:09 AM.
I am at 115k miles and mine had started doing the same thing.
Couldn't ever feel it under boost. I would describe it as feel like a strong gust of wind to the front of the car. Mine only does it when really cold now if at all. I always let the car warm up now to prevent it. I have a small exhaust leak. I cleaned the intake valves and that helped quite a bit, but they were not the culprit.
Couldn't ever feel it under boost. I would describe it as feel like a strong gust of wind to the front of the car. Mine only does it when really cold now if at all. I always let the car warm up now to prevent it. I have a small exhaust leak. I cleaned the intake valves and that helped quite a bit, but they were not the culprit.
New Member
Joined: 04-21-09
Posts: 156
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From: SoCal
I am at 115k miles and mine had started doing the same thing.
Couldn't ever feel it under boost. I would describe it as feel like a strong gust of wind to the front of the car. Mine only does it when really cold now if at all. I always let the car warm up now to prevent it. I have a small exhaust leak. I cleaned the intake valves and that helped quite a bit, but they were not the culprit.
Couldn't ever feel it under boost. I would describe it as feel like a strong gust of wind to the front of the car. Mine only does it when really cold now if at all. I always let the car warm up now to prevent it. I have a small exhaust leak. I cleaned the intake valves and that helped quite a bit, but they were not the culprit.
I am at 115k miles and mine had started doing the same thing.
Couldn't ever feel it under boost. I would describe it as feel like a strong gust of wind to the front of the car. Mine only does it when really cold now if at all. I always let the car warm up now to prevent it. I have a small exhaust leak. I cleaned the intake valves and that helped quite a bit, but they were not the culprit.
Couldn't ever feel it under boost. I would describe it as feel like a strong gust of wind to the front of the car. Mine only does it when really cold now if at all. I always let the car warm up now to prevent it. I have a small exhaust leak. I cleaned the intake valves and that helped quite a bit, but they were not the culprit.
It's only $80 to replace both and I know I should but I doubt it fixes it.
Have you been able to log the issue? I wonder if it's an issue with the varying tables not being smooth in the tune. You're tuned right?
New Member
Joined: 04-21-09
Posts: 156
Likes: 0
From: SoCal
Guess I'll find out for myself. My car has about 127k on it and the suspension has been untouched in all that time, so I figure some preventative maintenance (and maybe some upgrades) isn't an unreasonable thing to do. If it gets rid of the stumble problem as well, all the better.
Will report back as to if this solves my problem.
Will report back as to if this solves my problem.
I installed new Moog sway bar linkages and Moog control arms (I decided the latter was easier than just putting new bushings into the existing ones -- which I later discovered got dented somehow and needed replacing anyway). While I was at it, I decided to put in new OEM struts, shocks, and YYZ springs.
I hadn't even gotten around to putting in the new phaser solenoids yet, and after three weeks of driving I have yet to get a stumble. Not even once.
Kudos to Stamina. I would've never thought suspension issues would cause stumble issues.
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