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Discussion Starter · #1 ·
Has anyone had the following problem with their truck, if so what was the fix?
First of all my truck has 118,000 miles and I never towed a trailer; when cruising on the road at a constant speed for an extended period of time, the vehicle starts to decelerate although the accelerator has not changed position. In order to get the engine respond to the accelerator again I have to release peddle completely and reapply pressure to get back up to speed.
The check-engine light has never come on to indicate a problem, so I can’t determine if it’s a transmission or engine CPU management problem.
Any thoughts will be helpful.
 

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My first question would be, When does this happen? Are you going up a grade (hill)? When did this first start to happen? My advice would be to get a scan tool on it, and try to recreate the situation.
 

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Discussion Starter · #3 ·
It started last summer on a flat surface. I checked it with my scan tool and no codes were thrown. Do you have the tool hooked up and drive the vehicle?
 

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To answer your question: yes have it hooked up and drive it. Try and force the issue. Open all ids that correspond to the Throttle position, Cruse control, Trans mission and fuel system. You might not see any codes, but the pids don't lie. If you don't get anything on the pids. The next thing to look at is your fuel system, which should have been the first thing to eliminate. then the other process of elimination would be transmission maintenance, and finally the cruse control system.
 

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hmmm i wish i could help you with this issue, but i am at lose with the exception it sounds like a throttle position problem and/ or computer issue.. listen to Rustin though, he has better idea then I would.
 

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Scan tool PIDs info

Rustin,

Thanks for your suggestions, what are pids?
PID stands for parameter identification. Some scan tools will show graphs of what each parameter and/or sensor is doing.
Any good scan tool or software worth their salt has these features. For Dodges the scan tool of choice is the DRBIII. GM's scan tool is GM Tech 2, and My beloved Ford works well with the Star Tester. They all have extra features that most other scanners don't have, that is significant to the vehicle manufacturer. However; any Snap'on, Matco, Bosch, Pegisys, and autoenginuity will work fine.
For more info click on these links
Using the Auto-Scanner (scan tool) and PID (parameter) Interpretation

This next link will be to some power points that you can down load they might not give you the full info, but if you have any questions do google it or start another thread on it.
go to How to Teach Scan Tools and PIDs
 

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I had the same problem and I had to change the type of air filter. Power was restored.
I got to give you reps for that!:smileup:

Doggone it! I keep forgetting the basics! He is right! Always start with the basics first. So start with a good PM (Preventive maintenance checks and service) that means start with the Air cleaner, fuel filters, Batteries! It's amazing how old or faulty batteries cause some serious electrical hiccups! Not saying do a major tick just remind your self what has been done and ask your self do I need to check them? Chances are it is always something simple!
 

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Well when you get to checking your fuel pressure that should indicate of a problem. With fuel delivery (Vp-44, Fuel filter, Sending unit, etc etc).
 

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Discussion Starter · #13 ·
Thanks Rustin for the information you have provided. I think I figured out the problem, I had installed a Granatelli Big G Diesel Fuel power module a year ago. I disconnected this past weekend and drove for about 80 miles and had no problems. Your advice made me do a lot of think about what could be the problem.

Also thanks for the information about the various scan tools.
 

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Thanks Rustin for the information you have provided. I think I figured out the problem, I had installed a Granatelli Big G Diesel Fuel power module a year ago. I disconnected this past weekend and drove for about 80 miles and had no problems. Your advice made me do a lot of think about what could be the problem.

Also thanks for the information about the various scan tools.
Your very Welcome! At the very top right hand corner is a pair of weights. Click on it and give us some rep points for trying to help you.

I am very glad you found your problem. I had to put out the information in a way to help you decipher it yourself. There is no way we can actually diagnose a vehicle unseen. Thats why asking questions is the key. Sometimes we can get it figured out, and sometimes we are way off the mark. Critical thinking will have to be exercised when there is to much information. You can claim this find, all i did was ask questions. You did it all yourself.
 

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Reply to Unknown

I drive a 2008 6.7, I was on the highway about 1 year ago, and I lost all power. It did not stall, I Pulled off to the side of the highway, and called my dealer. He said to shut it off and restart after about 10-15 seconds. I did this and the next day went to the dealer, and like you there was no problems showing on his tests.
I have since found out that it was the electronic throttle, it had dis-engaged.

I have also been told the fault was mine. I had a tendency to at times put my left foot on the brake, while my right was on the throttle. The computer read this and didn't know to stop or go, and to avoid damage, it sent a message to disconnect my throttle. It was easly reset, and now I have better habits, it has never happened again.

Sorry for the long reply, I hope this might be your problem. PS I had no engine lite either.
 

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I drive a 2008 6.7, I was on the highway about 1 year ago, and I lost all power. It did not stall, I Pulled off to the side of the highway, and called my dealer. He said to shut it off and restart after about 10-15 seconds. I did this and the next day went to the dealer, and like you there was no problems showing on his tests.
I have since found out that it was the electronic throttle, it had dis-engaged.

I have also been told the fault was mine. I had a tendency to at times put my left foot on the brake, while my right was on the throttle. The computer read this and didn't know to stop or go, and to avoid damage, it sent a message to disconnect my throttle. It was easly reset, and now I have better habits, it has never happened again.

Sorry for the long reply, I hope this might be your problem. PS I had no engine lite either.
Interesting fact about these new trucks you brought up. It is true, they are trying to be smart. The software in some of these vehicles are designed to protect its self, even from the owner! It is evident that the software is getting encryption codes so that people will not tamper with the perimeters and sensors.
 
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