Help with a diagnosis please.
Thread Starter
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Tuned
Joined: Jan 2004
Posts: 465
Likes: 13
From: Hickory, North Carolina
Help with a diagnosis please.
When maintaining a steady speed of 40-42 MPH my truck is hesitating/skipping/stumbling/missing (pick one, it's hard for me to describe). I have no issues with acceleration, slow of fast. I have no issues below or above the 40-42 range. Any help is appreciated.
David
David
Fleet Mechanic
Joined: Jul 2010
Posts: 1,753
Likes: 34
From: Los Angeles, Ca.
What's your RPM at that speed and is the torque converter locked at that speed? When my converter is locked at low RPM, lowest it'll allow is a hair over 40mph, it feels a little bit stumbly, especially when I start to accelerate or maintaining speed on a hill. I think it's a normal thing for it, the RPM are just too low for it to run real smoothly and with the converter locked every pulse from the engine is being transmitted through the drivetrain.
If yours is stumbly with the converter unlocked then something's wrong.
If yours is stumbly with the converter unlocked then something's wrong.
Thread Starter
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Tuned
Joined: Jan 2004
Posts: 465
Likes: 13
From: Hickory, North Carolina
I have no clue, I'll have to get it checked.
This makes sense. I'll pay attention to it on the way home today. Any speed under or over, even 1-2 MPH it's fine. But around the 42 mark is when I notice it.
What's your RPM at that speed and is the torque converter locked at that speed? When my converter is locked at low RPM, lowest it'll allow is a hair over 40mph, it feels a little bit stumbly, especially when I start to accelerate or maintaining speed on a hill. I think it's a normal thing for it, the RPM are just too low for it to run real smoothly and with the converter locked every pulse from the engine is being transmitted through the drivetrain.
If yours is stumbly with the converter unlocked then something's wrong.
If yours is stumbly with the converter unlocked then something's wrong.
Laughing Gas
Joined: Jul 2018
Posts: 816
Likes: 7
From: Prescott, AZ
An OBDII adapter from Amazon, an Android or iPhone tablet or smartphone, and TorquePro or ForScan will give you all the data requested above except fuel pressure. And a whole lot of other diagnostic tools that will be extremely valuable in the future.
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