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Very Rough Start on Morning Cold Starts - Should I be concerned?

Condor757 said:
Try this procedure guys. It worked for me and haven’t had a rough start since.

OPTION TWO-RESET TPS & ACCELERATOR PEDAL (did once and works great so far)
1-Foot OFF of the brake and accelerator pedal
2-Press the START BUTTON until the RUN position is achieved but DO NOT start the vehicle. (If you do, turn off, open door and let everything reset before restarting).
3-Wait until all the instrument panels idiot/cycle lights go OUT (Check Engine light may stay on)
4-Slowly press the accelerator pedal all the way to the floor and then slowly let off. I think a steady and consistent motion is best.
5a-Press START BUTTON again to turn everything off. (Open Door?) Start the truck as normal. That should recalibrate the pedal so that you are using its full range of motion in synch with the throttle body's opening.
or
5b-Press Brake pedal and START BUTTON to start truck."
Click to expand...
Doesn't work in my case, done both by the procedure and at the dealer - no change.
 
NorthStar said:
I don’t see where you indicate the model year. If a 2019, see below which may be part of the problem:


5thgenrams.com

Truck almost stalls out when cold start?

I have 32K miles on my 5.7hemi longhorn and recently I have been experiencing really rough idle when I start her up and my truck literally almost stalls out. after 20-30 sec idle smooths out and then runs fine. Anyone experiencing this as well? suggestions?
5thgenrams.com 5thgenrams.com
Click to expand...
I have a 2021 Ram 5.7 and have had this cold start problem from day one. Bought it in January and just took it in last week Sept 2021. They told me nothing they could do cause it didn't throw a code and there is no service bulletins on this problem. When I first start the truck cold it stumbles off an idle for at least 10 minutes till warm. It will surge/race after the stumble making it unpredictable. Don't think its normal and could be a safety drivability concern.
 
Wolfmanwon said:
I have a 2021 Ram 5.7 and have had this cold start problem from day one. Bought it in January and just took it in last week Sept 2021. They told me nothing they could do cause it didn't throw a code and there is no service bulletins on this problem. When I first start the truck cold it stumbles off an idle for at least 10 minutes till warm. It will surge/race after the stumble making it unpredictable. Don't think its normal and could be a safety drivability concern.
Click to expand...
YES Wolfmanwon. Your wording better explains exactly what I experience with my truck. Mornings with a higher humidity seem to intensify the rough struggle my truck goes through. What baffles me is the most is for the first 3 years I had no problem with cold starts. Whether it was a hot mid-summer or bitter cold mid-winter morning she started up like a champ only up util about 6 months ago where this issue started out-of-the-blue and has been persistent since.
 
I had this issue on a previous Ram. A PCM flash cleared it up.
 
MValdez said:
I was referred to this procedure back when I first got my truck and installed swapped out the stock intake with the AFE stage 2 CAI and was experiencing sluggish throttle response. A member On this site said doing this would help calibrate the new map sensor of the cai. I will try this in the morning tomorrow. thanks for the tip.
Click to expand...
6 weeks later update
Condor757 said:
Try this procedure guys. It worked for me and haven’t had a rough start since.

OPTION TWO-RESET TPS & ACCELERATOR PEDAL (did once and works great so far)
1-Foot OFF of the brake and accelerator pedal
2-Press the START BUTTON until the RUN position is achieved but DO NOT start the vehicle. (If you do, turn off, open door and let everything reset before restarting).
3-Wait until all the instrument panels idiot/cycle lights go OUT (Check Engine light may stay on)
4-Slowly press the accelerator pedal all the way to the floor and then slowly let off. I think a steady and consistent motion is best.
5a-Press START BUTTON again to turn everything off. (Open Door?) Start the truck as normal. That should recalibrate the pedal so that you are using its full range of motion in synch with the throttle body's opening.
or
5b-Press Brake pedal and START BUTTON to start truck."
Click to expand...
*** This Works ***
UPDATE- I performed the TPS Reset and it worked like a charm! It has been 6 weeks now and my truck starts up every morning smooth and consistent, without even a hiccup.
 
FarmerJohn said:
Interesting post. I had a recent few rough starts with my 2020 Ram1500 5.7L, with 23k miles. I came here to look, and found posts regarding purge valve issues, etc… I had to buy low octane fuel prior to this tank. I’m guessing the fuel quality is the issue, and need to try another station and stick with the mid-level octane or higher. I’ll post a follow up when I can get another tank full through. Thanks NorthStar!
Click to expand...
weeks later, and not a single problem since. Just had to use medium grade octane.
 
Interesting. I was going to offer up what worked for my '97 when I had the very same issue. Mine turned out to be the Idle Air Control Valve. The first one was a bit gummed up, so cleaning the throttle body helped it along for another few months, but it eventually gave up. Then it turned into 2 more IACV replacements over the 15 years I owned that truck.

I'm not surprised that a few possible solutions to this issue seem to be software-related. And No, I'm not a fan of 'throttle-by-wire,' give me a proper throttle cable any day of the week.

Glad to hear you got it cleared up! Filing this thread away for future use if [hopefully not] needed.
 
Hate being that guy to bump an old thread, but I had this exact issue recently, and this forum post was top of my google search for my search criteria. So, I thought I’d share my experience. Note, I’m not an expert. Just an enthusiast.

Short story, this ended up being a bad tank of fuel for me.

Long story, I was having these exact problems. Seemingly out of the blue the very first start-up of the day (each day), the engine would start and idle very hard. Basically, like it was gasping for air, fuel, or both. At first it turned over no problem, but just idled very rough. As the days passed it got progressively worse, and finally basically plateaued. This issue was only present on the first cold start of the day. Once warm, it ran and idled without a hiccup.

The short-term fix for me was to immediately turn the truck off after the very first start of the day. 90% of the time it would start up just fine on the second attempt. The other 10% of the time I had to restart the truck twice. I did try cycling the ignition to the second position for 10 seconds a few times, but that didn’t seem to help.

Of course, I wasn’t completely clueless as to what this might be when it first started. Two distinct things happened to my truck the day before the issue presented itself. One, I got my fall oil change in. That went fine. I used PUP 5W-20 and an OEM Mopar oil filter. I always monitor oil pressure after a change, and it has been perfect.

The other thing I did was I fueled up a full tank of gas at an out-of-town gas station. I do run a 91 octane tune so naturally that’s what I fueled up on. The station was a “Top Tier” location, but the 91 octane there had a higher ethanol content (@ 15%) than what is typically in the fuel I use. Most of the stations I use in my hometown advertise 10% or less ethanol content so I didn’t think it would make that much of a difference. So, it was either that or it must have been just a flat-out bad tank of gas.

Anyways, I ran that tank of fuel down to empty, put in a bottle of Techron fuel cleaner, and a fresh tank of 91 octane at my go-to gas station. The first two days after filling up the fresh tank, I had some light sputtering on the first cold start of the day. By day three, the sputtering was completely gone, and the truck was back to sounding beautiful on cold starts.

Specs-

5th gen 2019 RAM 1500 Rebel w/ 14k miles (currently just a weekend toy)

Current (performance) mods
  • S&B cai
  • Borla Touring exhaust
  • Stock 91 octane tune + transmission tune from Diablo sport (MDS disabled)
Wants:
  • Long tube headers w/ cats
  • Hemi Fever tune
  • King/Icon suspension kit (if/when air susp fails)
  • catch can (ordered)
If (when) I go off the deep end:
  • cam
  • forged internals
  • 2800 torque converter
 
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