Engine almost stalls during cold start

[Thewetdream]

2022 5.7L 22k miles……..I posted the video on YouTube so you can hear what’s going on. No other running issues what so ever.

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[Fast69Mopar]

2022 5.7L 22k miles……..I posted the video on YouTube so you can hear what’s going on. No other running issues what so ever.

- YouTube

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What's is happening here can be caused by a number of things from low fuel pressure to a failing map sensor. Some diagnostics are in order to determine the root cause of this issue.

First off, does this situation occur on every cold start?

Does it occur any time after the first cold start of the day?

What modifications have been done to the truck?


Has the truck been tuned and by who or do you have a programmer installed with a "canned tune?

Is the check engine light on or does it ever flash after a cold start?

Have you attempted anything yet to find out what is causing this?

 

[Thewetdream]

Truck has to sit at least 4 plus hours for it to stumble on its face when starting. Truck has a cat back flow master exhaust and a s&b cai that’s been installed for well over a year, I run 91-93 octane fuel. Issue started this month. No check engine lights, no tune and I only attempted to calibrate the throttle which did not help or make the issue worse. Thank you guys for your time , maybe one of you had this issue and had figured it out.

 

[Fast69Mopar]

Truck has to sit at least 4 plus hours for it to stumble on its face when starting. Truck has a cat back flow master exhaust and a s&b cai that’s been installed for well over a year, I run 91-93 octane fuel. Issue started this month. No check engine lights, no tune and I only attempted to calibrate the throttle which did not help or make the issue worse. Thank you guys for your time , maybe one of you had this issue and had figured it out.

First thing I would do is check the fuel pressure. Make sure the truck has been sitting for at least the 4 hours before like you stated. Then...

Install a mechanical fuel pressure gauge.

Key On without starting the engine and watch the fuel pressure gauge and record the pressure.

Next, turn the key off and watch the fuel pressure to see if the pressure is bleeding down. If the pressure is bleeding down then we know the check valve in the pump has failed and is unable to maintain Key Off Engine Off fuel pressure.

If the pressure does not bleed off, start the engine while monitoring the fuel pressure gauge and watch the fuel pressure while the engine is stumbling.

Does the fuel system have proper pressure on startup while the engine is stumbling?

This is where I would start.