Low RPM bucking (misfire) no DTC
09-26-2008, 02:27 PM
#26
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To start off with your not very bright. You have just joined and you think you know more than a lot of older members on here. E-dick FTL.
Anyways my ss/tc seems to have a bit of a misfire too...could be normal for the LNF with the direct injection and all at slower speeds. No code has popped up for me either and I've had it 3000 miles so far. Though I am going to take out the plugs and check the gap on them I will report back with my findings.
Anyways my ss/tc seems to have a bit of a misfire too...could be normal for the LNF with the direct injection and all at slower speeds. No code has popped up for me either and I've had it 3000 miles so far. Though I am going to take out the plugs and check the gap on them I will report back with my findings.
09-26-2008, 04:06 PM
#29
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I think you must have ment rear wheel drive. You do not even know me so do not call me retarded. You are are most definately a condescending ***** from your posts I can tell this. If you do not have anything constructive to say do not say anything. The rwd. vs. fwd. dos not matter here we are not talking torque steer hare 
Thanks for the backup one this. He seems to think its funny for some reason. 
Thanks for the info. You are always so helpful blackbird. I guess I wish the car would run smoother at lower rpms. I have also noticed when its cold it bucks when I shift from first to second especially if I shift before 3000 RPM. 
To start off with your not very bright. You have just joined and you think you know more than a lot of older members on here. E-dick FTL.
Anyways my ss/tc seems to have a bit of a misfire too...could be normal for the LNF with the direct injection and all at slower speeds. No code has popped up for me either and I've had it 3000 miles so far. Though I am going to take out the plugs and check the gap on them I will report back with my findings.
Anyways my ss/tc seems to have a bit of a misfire too...could be normal for the LNF with the direct injection and all at slower speeds. No code has popped up for me either and I've had it 3000 miles so far. Though I am going to take out the plugs and check the gap on them I will report back with my findings.
I've noticed on my car that when cold and in 1st and 2nd gear at low speeds right after start up there's a little bit of driveline lash and bucking that is more noticeable with the A/C. I think that's normal though and is more than likely the engine calibration altering the timing and fueling to get the cat to light off faster. But if enough people take their car in for service then a manufacturer may sometimes try to release a flash/programming update but I haven't heard of anything so far for the new SS.
You can have light audible knock that won't damage an engine but it's hard to say it that's the case here. If you suspect knock or a misfire you could always try to monitor on a scan tool. I'd bet there probably isn't a problem with the car but you could always check the simple stuff like plugs and make sure there aren't any vacuum line or sensor issues. Also while the LNF pulls pretty well from low rpms and is very smooth, 1500 rpms is a little too low for 5th even though it will still pull the car on flat ground. It might just be a case of needing to modify your driving style, especially if you were used to higher displacement engines in the past that can inherently pull better at low rpms than a small displacement boosted engine.
You can have light audible knock that won't damage an engine but it's hard to say it that's the case here. If you suspect knock or a misfire you could always try to monitor on a scan tool. I'd bet there probably isn't a problem with the car but you could always check the simple stuff like plugs and make sure there aren't any vacuum line or sensor issues. Also while the LNF pulls pretty well from low rpms and is very smooth, 1500 rpms is a little too low for 5th even though it will still pull the car on flat ground. It might just be a case of needing to modify your driving style, especially if you were used to higher displacement engines in the past that can inherently pull better at low rpms than a small displacement boosted engine.
Last edited by Terminator2; 09-26-2008 at 04:06 PM. Reason: Automerged Doublepost
09-26-2008, 04:12 PM
#31
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Does your tune fix that low rpm misfire Psykotevo.
Which fuses. What do you think the problem may be?
Which fuses. What do you think the problem may be?
Last edited by Terminator2; 09-26-2008 at 04:12 PM. Reason: Automerged Doublepost
09-26-2008, 04:14 PM
#32
Haha, I was just kidding. You are just at WAY too low of an RPM. The S/C takes hp to run properly... at that low of an RPM, your engine just isn't making enough ponies to function properly. Same applies for the Turbo... our engines just aren't made to operate at those RPM's.
My RPM's don't drop below 2k when I'm driving... for this exact reason. You'll get better gas mileage if you keep it between 2250 and 2500 rpm anyway.
My RPM's don't drop below 2k when I'm driving... for this exact reason. You'll get better gas mileage if you keep it between 2250 and 2500 rpm anyway.
09-26-2008, 04:19 PM
#33
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^ Pretty much.
You're sort of right. The Redlines and SS/SC both have this issue as well.
The reason is that as the engine slows down, it will add fuel to try and keep RPMs above a certain range. Unfortunately, the PCM adds a lot of fuel, so it gives you that jolt forward until it's above the target RPM, followed by cutting out immediately, which results in the miss feel. This repeats until you apply more throttle so it is getting a constant throttle signal. This occurs around 1500 RPM from my experience.
Try cruising at 5 MPH in first gear, you'll see what I'm talking about. Your engine isn't misfiring, it's user error.
The reason is that as the engine slows down, it will add fuel to try and keep RPMs above a certain range. Unfortunately, the PCM adds a lot of fuel, so it gives you that jolt forward until it's above the target RPM, followed by cutting out immediately, which results in the miss feel. This repeats until you apply more throttle so it is getting a constant throttle signal. This occurs around 1500 RPM from my experience.
Try cruising at 5 MPH in first gear, you'll see what I'm talking about. Your engine isn't misfiring, it's user error.
09-26-2008, 04:19 PM
#34
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Somewhat. I know it still exists on some cars no matter what. Not all of the LNFs were built equally. And the motor is also prone to misfiring. Had a couple people complain about that before tuning, and then after tuning I'd say 80% of it is gone.
09-26-2008, 04:26 PM
#35
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09-26-2008, 04:29 PM
#36
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Haha, I was just kidding. You are just at WAY too low of an RPM. The S/C takes hp to run properly... at that low of an RPM, your engine just isn't making enough ponies to function properly. Same applies for the Turbo... our engines just aren't made to operate at those RPM's.
My RPM's don't drop below 2k when I'm driving... for this exact reason. You'll get better gas mileage if you keep it between 2250 and 2500 rpm anyway.
My RPM's don't drop below 2k when I'm driving... for this exact reason. You'll get better gas mileage if you keep it between 2250 and 2500 rpm anyway.
09-26-2008, 04:32 PM
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09-26-2008, 04:34 PM
#39
Jump in mine with a 2.8" pulley and it is a lot worse.
Last edited by USMCFieldMP; 09-26-2008 at 04:34 PM. Reason: Automerged Doublepost
09-26-2008, 04:35 PM
#40
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Actually the ss/tc does not make much tq at all at low low rpms in a higher gear....what makes all that tq down low is pushing some boost from a small turbo since typically your not in boost at those rpms in a higher gear your probably looking at a low low tq number haha. So the bucking is explainable...my ss/sc did this to a certain extent not AS bad but still done it. Not complaining about the car though its just the nature of the beast I guess....if a tune takes most of the misfiring out I will be getting that soon anyways. My guess is that where a DI engine does not pump in as much fuel as a regular fuel setup car and the AFR is much higher at operating speeds it is more prone to misfiring...not really spark related...this is just all assumption though.
Look at the instant MPG when your WOT haha its aweful.
Look at the instant MPG when your WOT haha its aweful.
09-26-2008, 04:36 PM
#41
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^ Pretty much.
You're sort of right. The Redlines and SS/SC both have this issue as well.
The reason is that as the engine slows down, it will add fuel to try and keep RPMs above a certain range. Unfortunately, the PCM adds a lot of fuel, so it gives you that jolt forward until it's above the target RPM, followed by cutting out immediately, which results in the miss feel. This repeats until you apply more throttle so it is getting a constant throttle signal. This occurs around 1500 RPM from my experience.
Try cruising at 5 MPH in first gear, you'll see what I'm talking about. Your engine isn't misfiring, it's user error.
You're sort of right. The Redlines and SS/SC both have this issue as well.
The reason is that as the engine slows down, it will add fuel to try and keep RPMs above a certain range. Unfortunately, the PCM adds a lot of fuel, so it gives you that jolt forward until it's above the target RPM, followed by cutting out immediately, which results in the miss feel. This repeats until you apply more throttle so it is getting a constant throttle signal. This occurs around 1500 RPM from my experience.
Try cruising at 5 MPH in first gear, you'll see what I'm talking about. Your engine isn't misfiring, it's user error.
09-26-2008, 04:37 PM
#42
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bad spark plugs-incorrect gap space? I can drive in 5th as low as ~1400 rpm but only experience what you describe if I get on-off the throttle, ... perhaps bad gasoline or lower than premium octane?
09-26-2008, 04:40 PM
#43
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09-26-2008, 04:42 PM
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I believe all cars are different could be the gas...I always use premium in mine though nothing less at all. Could be the gapping or just the ECM...eventually there may be a recall on them just have to wait and see....I say GM with their stage upgrade will fix a lot of issues that are occuring.
09-26-2008, 04:43 PM
#45
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I use only 93 octane fromm Mobile, BP, or Sunoco so that sould not be it. I will check my plug gaps thay may be too wide from the factory or maybe a bad set of plugs like you suggested.
09-26-2008, 04:51 PM
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09-26-2008, 05:33 PM
#47
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The way I measured it is only if I am maintaining or increasing in speed, @ 40 in 5th I can hit ~40mpg and still be accelerating (albeit very slowly). Trying the same @ 60 in 5th and its @ ~35mpg.
09-26-2008, 06:11 PM
#48
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why are you in 5th gear at 40mph.... your lugging the engine and if lugged hard enough it can scrape cyl walls (also known as piston slap) causing a loss of compression over time. shift into 4th /
09-27-2008, 12:32 AM
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lol all engines do this with high torque learn to drive it better and you will not get the buck. It is because of lack of experience with the Clutch. No Big Deal. It is normal. Try driving a mazda b4000 manual truck. Thing bucks like you can't believe.. 5th gear is meant for 55+ lol going 45 in 5th should make it buck at low RPMS slowing down, I would be pissed too if I had to go from 10 mph to 55+ starting in 5th ofcourse the tranny is gunna want higher RPMs it's not your moms Subaru ... Watch a semi truck take off with no load sometime.
I have this issue with my SS Turbo and I can guarentee it is NOT because of user error or too low of a gear. How do I know? Because I have been datalogging the MISFIRES that are registering every time I feel this - so I believe the original poster.
Haha, I was just kidding. You are just at WAY too low of an RPM. The S/C takes hp to run properly... at that low of an RPM, your engine just isn't making enough ponies to function properly. Same applies for the Turbo... our engines just aren't made to operate at those RPM's.
The reason is that as the engine slows down, it will add fuel to try and keep RPMs above a certain range. Unfortunately, the PCM adds a lot of fuel, so it gives you that jolt forward until it's above the target RPM, followed by cutting out immediately, which results in the miss feel. This repeats until you apply more throttle so it is getting a constant throttle signal. This occurs around 1500 RPM from my experience.
Try cruising at 5 MPH in first gear, you'll see what I'm talking about. Your engine isn't misfiring, it's user error.
Try cruising at 5 MPH in first gear, you'll see what I'm talking about. Your engine isn't misfiring, it's user error.
I need to check the gap on my plugs. I know in my case, this misfiring is not caused by bad gas - this has been ongoing, and due to the gas shortages in my area I have been filling up at every imaginable gas station over the last couple of weeks. (I had to go to SIX stations before I found one that had gas today!)
09-27-2008, 12:19 PM
#50
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After reading and posting in the thread earlier yesterday and thinking about it on the drive home last night, I take back what I was thinking of 1500-2k rpm being too low for fifth. On flat roads and light throttle acceleration during gentle cruising around town it's not a problem, but if you're at 75% throttle or more and trying to accelerate hard it probably would be best to downshift. I'd still maybe try to get a scan tool on it but I doubt there's anything you'll find wrong on the car and it's probably just the engine calibration. If it's really bad you could always take it into the dealer but if they don't find any mechanical or electrical issues and it is the cal they aren't going to be doing anything if GM hasn't released a new flash to correct drivability complaints.