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  #1  
Old 03-06-2014, 07:03 PM
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2013 JGC surging at freeway speeds

I recently purchased a 2013 JGC Limited with a Hemi 5.7 V8. I recently took it on a longer drive and noticed a slight surging between 50 - 70 mph when accelerating slightly. Normally, I would think it would go into passing gear but it hesitates and surges gently before accelerating. It is worse in the AUTO mode as opposed to the SPORT mode. I had it in AUTO, using the cruise control, and when it needed to accelerate up a hill, it started "bucking" until I disabled the cruise. I don't notice it as much in town, only on the freeway above 50.

I've seen some discussion about a PCM update that could be a "fix" that the dealer needs to do? I haven't taken it in yet but I want as much info as possible before my visit, because our local dealership is not known for great customer service.

Any help would be greatly appreciated.
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Old 03-07-2014, 10:48 AM
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Re: 2013 JGC surging at freeway speeds

There are a few things that need to be known to even guess at a possible diagnosis.

1. If you have at least 30k miles on your Hemi, have you replaced the spark plugs as recommended
by Chrysler with OEM plugs?
2. Are you burning 89 or higher octane fuel as recommended by Chrysler?

If you answer yes to both of these questions, then it sounds like you have a bad case of the " fishbite" syndrome that Chrysler is very aware of and has a TSB about and a re-flash of your PCM.

I have done all the above and had this TSB performed on my 2011 Ltd 2wd and this seemed to have cured it.

The reason I asked about the plugs and fuel octane is that serious fishbite(surging) issues will not be fixed with a reflash. Hemi plugs are copper core and have a 30k mile life. Several others on this forum and other forums recommend you replace the plugs with the same OEM plugs(or NGK plugs) because the platinum and iridium plugs do not work well with the Hemi. I used the NGK Copper core, same as the ones in the SRT8. There are 16 plugs and it cost about $90 dollars( if you change them yourself) The dealer charges a couple hundred bucks for this job.

The fuel octane seems to make a difference too. As tempting as it is to run the cheaper 87 octane is, the owners manual recommends 89 or better. I admit, when I was just daily driving my Jeep and gas prices here in lower Bama hover around $3.18 a gallon for 87, I would fill the tank and spend $70. When using the cruise and driving 65mph, the "fishbite" was really bad and seemed worse when the outside temp was colder than 46. I switched to 89 octane and it was not nearly as noticeable.

These are just some of the observations and experiences I have had with my GC Hemi. I am by no means an expert.
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1978 Chevy Corvette Indy Pace Car edition, 5.7 L82, 4speed
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Old 03-07-2014, 11:01 AM
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Re: 2013 JGC surging at freeway speeds

Can't thank you enough for your reply Todd.

I guess I should have posted more info. I bought the car used with 25K mile a few weeks ago. It was raining hard when I test drove it and I didn't notice the subtle surging.

I always use 89 or higher octane and I doubt that the previous owner replaced the plugs. I hadn't heard of the "fishbite" syndrome but that's another good reference for me when I get it to the dealer.

Here's an odd thing that happened yesterday. It was about 40 degree here in Washington state and I had pulled out of the garage to head to work. For the first 10 minutes, the car ran GREAT, then after it warmed up, the surging came back. Seems like your suggestion about temperature may be valid.

If you have any other suggestions, please let me know. The more prepared I am the better.

Thanks again
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Old 03-07-2014, 02:50 PM
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Re: 2013 JGC surging at freeway speeds

Yeah what you are feeling is a shudder from the transmission. Read the post Transmission Shudder This post really explains in depth about the very issues that you are having. Sometimes the updated software helps, like it did for me, and sometimes it does not. I hope you have good results like I did.

It seems that Chrysler initially thought if they could keep the transmission in lockup all the time, they could get the mpg numbers up to help with the CAFE required regulations for fuel economy. The torque converter stays locked up when it should release and force a downshift to bring the engine back into the power band. The flash seems to help correct this, but you may see a small to moderate drop in fuel economy. To me, the smoothness of the ride far out weighs the MPg factor. If I have to tolerate this shudder just to get a few more MPG's, I'd rather loose a few MPG!
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Old 04-03-2014, 04:57 PM
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Re: 2013 JGC surging at freeway speeds

I finally had the update done and lost about 2 -3 mpg's. BUT....it still surges!! It's a little better but this is VERY annoying to spend this kind of money on a vehicle that surges along most of the time. It's funny, but before it's warmed up in the morning, it runs GREAT! Then after about 10 minutes the surging and hesitating comes back.
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Old 04-23-2014, 03:26 PM
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Re: 2013 JGC surging at freeway speeds

Hmm, my Jeep did not suffer any loss of MPG's and the surge is pretty much gone. The only time I get a little is when climbing a very steep grade and the tranny has not come out of lock up. Living close to the coast there is not a lot of steep hills around here and so that may be where our results differ.
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