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Rough Idle/ Bucking

farmingdalesfinest

farmingdalesfinest

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I bought a new 2500 Bighorn with the 6.4 engine in November. I have 6240 miles on it as of today.

I have noticed in the last couple of weeks that if I don't warm it up with the remote start as I leave my house or office and the extra time it takes to put the seatbelt and my phone in the charger it often bucks and the idle races. Today it was particularly bad and I started looking for causes. I am about to do my second oil change and came upon a thread about Lubegard for Hemi tick on another site. I looked it up and the one they make for Turbo engines they described in a video almost exactly what I have experienced but the one people are using for the Hemi tick doesn't talk about it. The first oil change was with Mobil 1 0w40 Euro and ordered the Euro Castrol Edge today to see if the idle will be quieter. It's much louder engine than my 14 1500 with the 5.7 but I wouldn't say I have the Hemi tick.

Has anyone else experienced this and what was the solution? Do I have a real issue or does it just need to run a little longer than I have let it sometimes?
 
I bought a new 2025 2500 Bighorn with the 6.4 engine in November. I have 6240 miles on it as of today.

I have noticed in the last couple of weeks that if I don't warm it up with the remote start as I leave my house or office and the extra time it takes to put the seatbelt and my phone in the charger it often bucks and the idle races. Today it was particularly bad and I started looking for causes. I am about to do my second oil change and came upon a thread about Lubegard for Hemi tick on another site. I looked it up and the one they make for Turbo engines they described in a video almost exactly what I have experienced but the one people are using for the Hemi tick doesn't talk about it. The first oil change was with Mobil 1 0w40 Euro and ordered the Euro Castrol Edge today to see if the idle will be quieter. It's much louder engine than my 14 1500 with the 5.7 but I wouldn't say I have the Hemi tick.

Has anyone else experienced this and what was the solution? Do I have a real issue or does it just need to run a little longer than I have let it sometimes?
 
Trash Panda said:
Post a video of what you’re experiencing.
Click to expand...
I'll try but it happens most often as i am driving away from my house or office and almost immediately I am turning into traffic which would make it hard at the least and ofetn dangerous to pull out my phone and try and film with other cars moving or when it lurches I am trying to make sure I don't hit a parked car.
 
Hi there, @farmingdalesfinest!

If looking for additional support in combination with your dealer appointment, then please let us know via private message. We're here to help.

Hannah
Ram Cares
 
Merged both duplicate posts into this single thread.

@farmingdalesfinest please refrain from creating duplicate posts. If you do so accidentally, please submit a moderator report and request that the duplicate be deleted.

If you have any questions, please feel free to reach out to me or the other admins / moderators.
 
Hello Farmingdalesfinest. I joined this forum specifically to find the answer to the problem you have. See my post

Warmup fast idle and surge or lurch in 1 and 2 gear range.​

I can tell you that it is definitely not the oil and you are not dreaming it. I have had mine at (4) different dealerships and the last two definitely confirmed it, escalated it to the manufacturer, where my vehicle now resides on a "list" of known VINs with this issue they have no solution for. It is programming for sure. All vacuum leaks checks etc. performed and there are none. It is PCM driven. When the vehicle starts to buck or lurch simply putting your foot on the brake and "whoa" like an unruly horse, straightens it up. I will share the best dealer tech description I have with everyone. Let's keep this thread alive as hopefully others will join and maybe we can solve it.
 

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farmingdalesfinest, out of curiosity, can you provide some details of your trucks warmup? For example, at what RPM does it rev to upon cold start? How long does it take for the engine to warm up and slow to idle rpm? what is your fully warmed idle rpm? I will re-evaluate mine, but i will have to make sure I have a full tank of fuel!!! :) As I seem to recall from previous observations with a watch it starts out at about 1200 and does not reach the ~750 rpm idle speed for at least 6 to 7 minutes. INSANELY out of spec. I would like to compare to what you are experiencing.
 
J.W.B said:
farmingdalesfinest, out of curiosity, can you provide some details of your trucks warmup? For example, at what RPM does it rev to upon cold start? How long does it take for the engine to warm up and slow to idle rpm? what is your fully warmed idle rpm? I will re-evaluate mine, but i will have to make sure I have a full tank of fuel!!! :) As I seem to recall from previous observations with a watch it starts out at about 1200 and does not reach the ~750 rpm idle speed for at least 6 to 7 minutes. INSANELY out of spec. I would like to compare to what you are experiencing.
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I have never seen it drop below 1000 rpm’s. It takes on mine over a minute to get down to about 1100. I never purposely let it go more than 2 minutes unless I am waiting for someone.
 
Timed mine again today. From cold start, 6M 45sec to idle down start. Meaning at 6.75 minutes after starting, it started decent to normal idle speed of 650 rpm. I know I will have to solve this problem as most, on my own, or at least tell the dealership exactly what needs to be remedied with the idle. Currently, I am thinking there is an issue with my idle speed target table. The ECT vs RPM specifically. I am collecting info from others to help confirm my suspicions, but essentially, I am confident we just need to reload some of the tables. Very frustrating what it takes to get something seemingly so simple done by a competent dealership. Thank you for your feedback.
 
hoping ....that there are some genuinely interested and capable RAM technicians familiar with the 6.4 HEMI in particular, that scan these forums. Fingers crossed.
 
J.W.B said:
Timed mine again today. From cold start, 6M 45sec to idle down start. Meaning at 6.75 minutes after starting, it started decent to normal idle speed of 650 rpm. I know I will have to solve this problem as most, on my own, or at least tell the dealership exactly what needs to be remedied with the idle. Currently, I am thinking there is an issue with my idle speed target table. The ECT vs RPM specifically. I am collecting info from others to help confirm my suspicions, but essentially, I am confident we just need to reload some of the tables. Very frustrating what it takes to get something seemingly so simple done by a competent dealership. Thank you for your feedback.
Click to expand...
Your question earlier got me thinking because I had never seen it drop below 1000 rpm while warming up. I had seen it lower as I said while waiting for someone to come out of our house. Tonight I had to move the truck because the new moon caused tidal flooding. I let it warm up about a minute and drove around the block to park a couple houses up the block where it’s higher ground. When I parked I watched it idle another minute and it still was at 1000 rpm.
 

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Thank you for the feedback. That is definitely excessive. If you do ever feel like burning an extra gallon of gas :) try starting from a cold start and with stopwatch running, just let her run until it idles down. Should be less than 10 mins. Mine idles down like you would expect one to do after 60 -90 seconds, but for me right around the 6.75 minute mark. It would be a good data point if they were the same. Further narrowing it to a specific program and not a phantom intake leak etc.
 
I like the info cluster on yours btw, more modern looking than my 2025 bighorn 3500. I have the smaller info center in the middle and a couple more semi analog gauges. Other than this idle thing, I am pretty happy with the rig so far. Pulls my boat and my ~9500lb RV with ease. Some expected (for a gaser) downshifts and high revs in the hills, but not enough to keep me from going plenty fast for the load. I never run that Rv over 75mph anyways but i could if I was nutty enough to try.
 
J.W.B said:
I like the info cluster on yours btw, more modern looking than my 2025 bighorn 3500. I have the smaller info center in the middle and a couple more semi analog gauges. Other than this idle thing, I am pretty happy with the rig so far. Pulls my boat and my ~9500lb RV with ease. Some expected (for a gaser) downshifts and high revs in the hills, but not enough to keep me from going plenty fast for the load. I never run that Rv over 75mph anyways but i could if I was nutty enough to try.
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My truck is a 25 Bighorn 2500. I would have expected the cluster to be the same in your truck too. I did almost 1900 miles in the last week. I went from NJ to Ohio for a few days and then had some longer than average drives this week when I got home with work. It was either in West Virginia or Ohio but there was a long steep hill and I saw a sign that said below 55 put your blinkers on. I looked down and I was going with the flow of traffic doing over 80. I decided to see if it would accelerate more as the hill got steeper and with the pedal less than 1/2 way down I was doing 94. That was the fastest I have driven it so far and it was absolutely effortless. That made me wonder what the top speed is if they didn’t have a limiter and what the limiter is set at. Even with those speeds I averaged 15.9 mpg for the trip with the 6.4 and 3.73 gears.
 
Dang!! I'd take that kind of mpg in a heartbeat! I have seen some fuel mileage testing online that match your numbers. Mine has improved, but best ever is ~14.5 mpg on fairly flat drive from Belton Texas to South Pittsburg Tennessee. Maybe hit 15 in some spots. for the most part I average ~10-12 in town and up to ~14.5 highway, but empty and no real hills. Put my ~9k Rv behind it and ~6-8 mpg. I kinda thought that was to be expected, but it sounds like maybe when I finally get it running right I could possibly expect better. Sounds like yours is already performing nicely concerning MPG. I really appreciate the information and if/when I get this idle thing solved I will share the fix. I am determined.
 
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