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Discussion Starter · #1 ·
I was wondering if any other '09 R/T owners have noticed this or not (or even other years for that matter). Sometimes while stopped at idle, the RPMs will surge and the car moves forward slightly, like you're pressing on the throttle and brake at the same time.

The car doesn't really move forward, but it is annoying when pulling into a parking stall or when stopped at a red light. I checked the list of TSB's out for '09 and haven't seen anything related to this yet.
 

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Yeah, I've noticed this happening with my '09 R/T as well. It doesn't happen very often, and it seems to be totally random, but it's kind of unsettling. Makes you feel like you need to step on the brake pedal harder to keep the car from moving forward. Almost like you're trying to do a brakestand.
 

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I have an 09 RT and haven't noticed anything...if I do I'll be sure to post here.
 

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I was wondering if any other '09 R/T owners have noticed this or not (or even other years for that matter). Sometimes while stopped at idle, the RPMs will surge and the car moves forward slightly, like you're pressing on the throttle and brake at the same time.

The car doesn't really move forward, but it is annoying when pulling into a parking stall or when stopped at a red light. I checked the list of TSB's out for '09 and haven't seen anything related to this yet.
This is simply an educated guess, but the 09s and up use Deceleration Fuel Cutoff. It is basically where the engine has deceleration fuel shut off and camshaft controlled charge trapping. It is designed to save fuel and also reduce NOx during deceleration and idle. It can only be used in an engine that has variable valve timing and electronic throttle control.

This is the case with the 09 and later Chargers.

It could at least be a clue here.:bigthumb:

Regards,
Brian
BND Automotive LLC:driving:
440-821-9040
 

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Discussion Starter · #5 ·
This is simply an educated guess, but the 09s and up use Deceleration Fuel Cutoff. It is basically where the engine has deceleration fuel shut off and camshaft controlled charge trapping. It is designed to save fuel and also reduce NOx during deceleration and idle. It can only be used in an engine that has variable valve timing and electronic throttle control.

This is the case with the 09 and later Chargers.

It could at least be a clue here.:bigthumb:

Regards,
Brian
BND Automotive LLC:driving:
440-821-9040
That's a good place to start, but the only problem is that this happens at random, well after any deceleration has occured. I'd hope that this isn't just the nature of having such a feature, as it is quite noticeable and a little annoying.

I may drop it by the dealer if I get some spare time in the coming weeks. Otherwise I'll just keep checking out the list of TSB's for the LX's.
 

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Discussion Starter · #6 ·
Yeah, I've noticed this happening with my '09 R/T as well. It doesn't happen very often, and it seems to be totally random, but it's kind of unsettling. Makes you feel like you need to step on the brake pedal harder to keep the car from moving forward. Almost like you're trying to do a brakestand.
I have an 09 RT and haven't noticed anything...if I do I'll be sure to post here.
Just a thought, what are the production dates for your vehicles?

Ours was manufactured in October 2008.
 

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i've got an 07 R/T n she does the same thing, from time to time...still catches me off guard,find myself pressin harder on the brake..lol thinkin i let off n im rollin into traffic...
 

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Mine is a mid-Feb. '09 build date.
 

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Are you running the A/C (even in auto)? Each time the compressor turns on I notice the idle jump up slightly. If my foot's not securely on the brake it can make the car roll forward.
 

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Are you running the A/C (even in auto)? Each time the compressor turns on I notice the idle jump up slightly. If my foot's not securely on the brake it can make the car roll forward.
I noticed it also. I have my idle turned down to 600rpm and i thought it was when the fans kicked on/off or the blower motor for the HVAC system was turning on for auto mode control. Of course I also think part of mine is my cam too.
 

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My car does it even with the A/C off, and independent of what the fans are doing.
 

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Discussion Starter · #12 ·

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I've seen many of these "phantom bump" issue threads since back in '06 and the one thing I've never seen:

Are any of you experiencing this in Autostick mode?

I use Autostick when I slow down and excellerate, every time and I have NEVER had the sensation of a surge when stopped when 75% (if not more) on this forum say they have.
 

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Discussion Starter · #15 ·
Need more info. How many rpm's increase? Cold. Hot. While warming up?
It's completely random, regardless of ambient or engine temperature.

Typically when it happens the idle is a little low (right at the 500 RPM hash mark) , but it will bump up to just above idle, then settle back into to the normal idle range. So I'd say it surges between 200 and 300 RPM's on average.

I've seen many of these "phantom bump" issue threads since back in '06 and the one thing I've never seen:

Are any of you experiencing this in Autostick mode?

I use Autostick when I slow down and excellerate, every time and I have NEVER had the sensation of a surge when stopped when 75% (if not more) on this forum say they have.
Yes, I have noticed this happen in Autostick or full automatic, and like I have mentioned before, it is completely random. I can go two to three days without it happening or have it happen at least once several days in a row.

One thing I have noticed is that the backlighting to the dash seems to flicker a bit when they're on at night. I also occasionally catch the cruise control icon flicker as well. This usually happens when the RPM's are lower than normal, so I am begining to wonder if I am having an issue with the charging system.

The secret menu shows that the voltage bounces between 13.3 and 14.6 during idle, however it remains fairly steady when accelerating or cruising between 13.9 and 14.4. I know that Chryslers use the ECM to regulate charging voltage, so a little bit of variance is normal based on current vehicle needs, but dipping into the low 13 volt range is a little concerning. I've seen that if the battery is unable to supply a steady source of power to the ECM on some Chryslers that it causes goofy alternator output and idle speeds, so I may try cleaning up the battery terminals (even though there are no signs of corrosion or oxidation) just to ensure that the connection is good.
 

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Sounds like a random surge with the related info. Difficult to diagnose. I'd try a shop I trust for one of those diagnostic plug-ins that can be put in the car for a week to record codes while driving when this intermittent problem happens. When read, it provides info for a qualified tech to solve. Good luck, let us know the final on this.
 

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Discussion Starter · #17 ·
Sounds like a random surge with the related info. Difficult to diagnose. I'd try a shop I trust for one of those diagnostic plug-ins that can be put in the car for a week to record codes while driving when this intermittent problem happens. When read, it provides info for a qualified tech to solve. Good luck, let us know the final on this.
Yeah, like I mentioned, I'll probably just clean up the battery terminals real well and see what happens from there. If I still have the same issue, I'll drop it by the dealership and let them deal with it.
 

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The secret menu shows that the voltage bounces between 13.3 and 14.6 during idle...
This is most likely a symptom of low idle speed rather than a cause. The alternator requires a minimum RPM to maintain the proper voltage output. When the alternator spins below the minimun, there's nothing it can do to make more voltage. It is going to starve just like all the other RPM dependent accessories.
The unstable idle sounds like a programming issue or an intermittent component that the ECM is heavily compensating for to maintain idle. I hope someone finds the cause soon for those who are dealing with the problem.
 
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