RPM's hang indefinitely between shifts

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Jeremymyers1988

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New to the forum here and jumping right into a problem I cannot solve. The RPM's in my 04 5.7L 5spd has recently started to hang indefinitely between shifts. If I shift into neutral at any RPM it will stay at that RPM until I go to a complete stop then it goes back down to idle. This happens in every gear and every rpm. I initially thought my throttle body was sticking so I replaced it, then a vacuum leak but I couldn't find one by spraying carb cleaner around all vacuum fittings. Also it has zero hesitation at any RPM or when driving.

When I bought the truck I would shift and go into neutral the RPM's would raise 300-500 or so then drop. I didn't think much of it but it no longer does that now since this new issue.

In the last year I've replaced the cats, o2 sensors, muffler, map sensor, spark plugs, coil packs, and various other sensors.

Is there any reason my RPM's would be hanging in neutral only when moving? I did do a quick test today going down the road about 15 miles an hour by putting the truck in neutral when it was hanging at 2k RPM's, turned the engine off and restarted. The truck went to about 1K then jumped back to to 2K while still in neutral. I may try this again tomorrow on a back road to confirm that I'm not crazy.

I hope I'm missing something simple and someone can make me feel stupid here.
 

moezer

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Throttle position sensor

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moezer

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U not getting any codes? Try the disconnecting the battery method

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Jeremymyers1988

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No codes which makes this difficult and I tried resetting the battery as well by shorting the leads together.
 

Fast69Mopar

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New to the forum here and jumping right into a problem I cannot solve. The RPM's in my 04 5.7L 5spd has recently started to hang indefinitely between shifts. If I shift into neutral at any RPM it will stay at that RPM until I go to a complete stop then it goes back down to idle. This happens in every gear and every rpm. I initially thought my throttle body was sticking so I replaced it, then a vacuum leak but I couldn't find one by spraying carb cleaner around all vacuum fittings. Also it has zero hesitation at any RPM or when driving.

When I bought the truck I would shift and go into neutral the RPM's would raise 300-500 or so then drop. I didn't think much of it but it no longer does that now since this new issue.

In the last year I've replaced the cats, o2 sensors, muffler, map sensor, spark plugs, coil packs, and various other sensors.

Is there any reason my RPM's would be hanging in neutral only when moving? I did do a quick test today going down the road about 15 miles an hour by putting the truck in neutral when it was hanging at 2k RPM's, turned the engine off and restarted. The truck went to about 1K then jumped back to to 2K while still in neutral. I may try this again tomorrow on a back road to confirm that I'm not crazy.

I hope I'm missing something simple and someone can make me feel stupid here.
As a Chrysler Technician, I have seen this complaint multiple times from plenty of my customers.

This is considered normal operation of the 5.7 HEMI ETC, or Electronic Throttle Control. Most of the reasons that this occurs is because the PCM keeps the engine RPM up to continue burning the remaining injected fuel in the cylinders to prevent rich spikes in the oxygen sensors and to prevent loading the catalytic converters with fuel.

The only way to eliminate this is with custom tuning. I use HP Tuners for the majority of my tuning and I can keep this from happening with changes in the tune. A forum friend of mine from the HP Tuners forum helped me figure it out and showed me what to change in the tune.
 
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Jeremymyers1988

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Is there a reason why it didn't start until a year after owning the truck?
 

LoneWolf3574

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Is there a reason why it didn't start until a year after owning the truck?
Dirty/clogged injectors maybe? That's just a guess though, that being said, it wouldn't hurt to run a bottle of your preferred injector cleaner through the tank.
 

Fast69Mopar

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Is there a reason why it didn't start until a year after owning the truck?
I have never been able to get an answer from my Zone Tech about the reasons of when or why it starts. I have 7 different trucks. Three of them are 5.7 trucks. Two are 4.7 trucks and the other two are 5.9 gas motors. One of the 5.7 trucks didn't start doing it until about 67,000 miles and the other two HEMI trucks have done it since they were new.

This issue is normally something drivers and owners don't realize is happening in the beginning. Most drivers don't move the shifter from Drive to Neutral while still rolling under power so they never see it happen.

If you ever do start tuning on your own with HP Tuners, what you will want to change in in the Torque Model Friction Table and you will need to use a negative value in the table.
 
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Jeremymyers1988

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I have never been able to get an answer from my Zone Tech about the reasons of when or why it starts. I have 7 different trucks. Three of them are 5.7 trucks. Two are 4.7 trucks and the other two are 5.9 gas motors. One of the 5.7 trucks didn't start doing it until about 67,000 miles and the other two HEMI trucks have done it since they were new.

This issue is normally something drivers and owners don't realize is happening in the beginning. Most drivers don't move the shifter from Drive to Neutral while still rolling under power so they never see it happen.

If you ever do start tuning on your own with HP Tuners, what you will want to change in in the Torque Model Friction Table and you will need to use a negative value in the table.


So the only fix for this is with a tune?
 
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Jeremymyers1988

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I guess the next question is if I purchase the HP Tuners MPVI2.. Is there a simple how to on what numbers need changed in the Torque Model Friction Table? I'm not looking to add any performance just drive-ability.
 

Fast69Mopar

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I guess the next question is if I purchase the HP Tuners MPVI2.. Is there a simple how to on what numbers need changed in the Torque Model Friction Table? I'm not looking to add any performance just drive-ability.
Tuning with HP Tuners is not easy. There is a ton of trial and error even for experienced tuners. When I am tuning a truck and making changes to the tune they may be different for each truck depending on how the vehicle reacts to the changes.

I recommend speaking with a reputable tuner. This is something I prefer to do with the vehicle in front of me instead of emailing tune revisions back and forth. It's not always the easiest to get the Rev Hang ironed out.

Where are you located?
 
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Jeremymyers1988

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Great news.. It's fixed! Turns out the power steering pressure sensor was leaking internally and shorting out the contacts inside the connector. After 2 weeks it finally threw a P0551 code for that sensor. I removed the connector and fluid actually came out of it. Learned that the sensor increases idle speed to prevent it from stalling when the pressure is out of wack. Who knew..

Now that my brain is fried from this.. I appreciate the feedback from everyone.
 

Redtruck-VA

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That's funny I use to use the power steering switch to up my idle on the 03 pcm. I used a rpm window switch to open and close the PS switch. Back in the day big cams and 03 pcm was a bad combo. I also remember a guy did a manual trans swap and had a hanging idle. I believe he fixed it with a pcm update. I briefly had the problem and a cmr tuner fixed it. This was years ago and don't remember what he said he did in the tune. I now use HP and haven't given it a thought. Glad you fixed it..
 
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