Sponsored

Cold Start Idle Speed

Rubicon6MT

Well-Known Member
Joined
Apr 14, 2025
Threads
9
Messages
54
Reaction score
17
Location
Canada
Vehicle(s)
Gladiator Rubicon
After a cold start, I always wait until the engine RPM drop before beginning to drive.

In warmer weather, the low idle speed was always 600 RPM.

I’ve noticed as the weather has gotten colder the engine now wants to idle at 900 RPM.

It seems like I would have to wait a long time for the 900 RPM idle to drop down to 600 RPM.

Has anyone else noticed this, and if so, any explanation?
Sponsored

 

Gvsukids

Well-Known Member
First Name
Justin
Joined
Mar 7, 2020
Threads
26
Messages
7,265
Reaction score
6,901
Location
Grand Rapids
Website
www.youtube.com
Vehicle(s)
2020 Gladiator Sport S Max Tow
Occupation
Delivery Driver

Gvsukids

Well-Known Member
First Name
Justin
Joined
Mar 7, 2020
Threads
26
Messages
7,265
Reaction score
6,901
Location
Grand Rapids
Website
www.youtube.com
Vehicle(s)
2020 Gladiator Sport S Max Tow
Occupation
Delivery Driver

Sponsored

nanook12

Well-Known Member
Joined
Jan 6, 2024
Threads
5
Messages
283
Reaction score
301
Location
Alaska
Vehicle(s)
2023 Jeep Gladiator Rubicon
Occupation
Retired
After a cold start, I always wait until the engine RPM drop before beginning to drive.

In warmer weather, the low idle speed was always 600 RPM.

I’ve noticed as the weather has gotten colder the engine now wants to idle at 900 RPM.

It seems like I would have to wait a long time for the 900 RPM idle to drop down to 600 RPM.

Has anyone else noticed this, and if so, any explanation?
what engine are you referring to?
 

DylanM

Well-Known Member
First Name
Dylan
Joined
Sep 1, 2023
Threads
1
Messages
1,025
Reaction score
2,559
Location
Texas
Vehicle(s)
'21 JTRD
Occupation
USAF Retired
Your engine idles at a higher rpm because the PCM is programmed to do so when the weather is colder for better/quicker warm up. Don't fret about it. Just start her up, wait a moment for the initial 1000+ rpm surge to subside then drive off.
Sponsored

 
 







Top