Engine surges on start up

[BigG]

Hello everybody. Seems like it happens mostly when the outdoor temperatures warm up. After start up an I’m letting the engine warm up, then the engine will start surging, a rise and lowering of RPM’s. It’s do it for about 30 seconds and then it runs smooth. It doesn’t do it on every start up. Any ideas as to what’s causing this? It’s a 2019 Ram Laramie. 5.7 hemi, 60,000 miles.

 

[tron67j]

Different parts could be causing this, from a PCV valve to other control units. Have you run diagnostics for any codes?

 

[BigG]

It’s been a while since I ran codes and nothing showed up. I’ll have to rerun them again soon.
Thanks

 

[huntergreen]

Is the AC on when you start it ?

 

[Atcer2018]

If it was your lawnmower I’d say clean the carburetor lol
Surging is typically a poor air fuel delivery. Unfortunately on modern vehicles it could be any number of things from a sensor to a clogged injector. Without diagnostics it’s pretty impossible to give advice but let me ask if you’ve ever checked the intake manifold bolts. They can become loose and that allows air to be sucked past the seals changing the air/fuel mixture after the metering at the throttle body. Once the engine warms up and things expand it seals again and runs smooth. It’s super simple to check them and only takes a few minutes of time. I’m probably way off in left field but it can’t hurt to check.

 

[Daw14]

When you finish tightening your intake manifold to 108 inch pounds . You should take a look inside your throttle body ,it may need cleaning. But definitely check the intake.

 

[BigG]

1) the ac is always off on start up in the am
2) about a year ago I used a bottle of throttle body cleaner; it didn’t seem to make a difference. Throttle body already appeared clean.
3)I will definitely check into the intake manifold bolts.
Thanks all!

 

[turkeybird56]

1) the ac is always off on start up in the am
2) about a year ago I used a bottle of throttle body cleaner; it didn’t seem to make a difference. Throttle body already appeared clean.
3)I will definitely check into the intake manifold bolts.
Thanks all!

Definitely run for codes. Besides loose intake bolts (maybe), what comes to mind for me is a bad sensor. My 2019 puked an O2 sensor. Took to dealership, they replaced the "indicated" sensor. I drove 1/4 mile down the road to BK to get a Burger, and alas, another MIL, same problem. Dealership replaced all 4 O2 sensors and no issues in years. Poor fuel also sometimes causes starved engine to push for more fuel in these rolling computers. (Just thinking out loud). But it just might be some other wacky sensor being a "butt", lol.

ADDED: Do you keep your Heat/AC set to Auto? Though no way that should effect an idle.

BIG G: Your Avatar lists 2014.

ATTACH: Intake bolt tightening sequence, in case U did not have and choose to check them out. Lil blue locktite helps too.

 

[RamDiver]

There are several great suggestions above but one other basic item to check, inspect the air filter.

Your truck will likely automatically compensate for a compromised air intake, but everything has limitations.

.

 

[turkeybird56]

There are several great suggestions above but one other basic item to check, inspect the air filter.

Your truck will likely automatically compensate for a compromised air intake, but everything has limitations.

.

Clint Eastwood: Man needs to know his limitations, lol. Were U able view pics?

 

[BigG]

Yes, I’m leaning toward the sensors also.
My fuel mostly comes from SAMS.
I always run the ac on Auto.
Thanks for the bolt attachment, it’ll help.
I’m usually on top of the air filter, but good suggestion, it’ll be checked again.
Thanks

 

[Wild one]

1) the ac is always off on start up in the am
2) about a year ago I used a bottle of throttle body cleaner; it didn’t seem to make a difference. Throttle body already appeared clean.
3)I will definitely check into the intake manifold bolts.
Thanks all!

If you have a 5/16" nutdriver,go over your intake bolts,if you can twist any of them with a nutdriver,then they should be re-torqued

 

[Sherman Bird]

Hello everybody. Seems like it happens mostly when the outdoor temperatures warm up. After start up an I’m letting the engine warm up, then the engine will start surging, a rise and lowering of RPM’s. It’s do it for about 30 seconds and then it runs smooth. It doesn’t do it on every start up. Any ideas as to what’s causing this? It’s a 2019 Ram Laramie. 5.7 hemi, 60,000 miles.

You've seemingly been chasing this for quite some time. Maybe, just maybe, you would benefit from having it properly diagnosed by a true professional....

 

[Sherman Bird]

Clint Eastwood: Man needs to know his limitations, lol. Were U able view pics?

You gotta ask yourself "Do I feel lucky"!

 

[Tominator223]

Could be a lazy 02. Air filter should be done about 20-30k depending on driving conditions. You can also spray wD-40 around intake , if it revs you found a leak. And it won’t hurt anything. Also a lazy 02. May not throw a code.

 

[Sherman Bird]

Could be a lazy 02. Air filter should be done about 20-30k depending on driving conditions. You can also spray wD-40 around intake , if it revs you found a leak. And it won’t hurt anything. Also a lazy 02. May not throw a code.

The last new truck I bought was in 2008. Since I buy older, typically high mileage vehicles these days, I see more than my share of "Lazy" oxygen sensors. I have been replacing all 4 of them on the vehicles I've bought over the past 8 or so years. The improvement in driveability and uptick in fuel mileage are notable improvements.

 

[Musky Mike]

Someone else jump in if I'm wrong. Truck starts up in open loop (no o2 input) until it reaches temp, then switches to closed loop (o2 input).

 

[Dusty]

Someone else jump in if I'm wrong. Truck starts up in open loop (no o2 input) until it reaches temp, then switches to closed loop (o2 input).

You are correct, although I think there's a time-out regardless of temperature feedback.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 113011 miles.