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Discussion Starter · #1 ·
Hey everyone! Im having issues with my 8 speed SRT 392. When I floor it, it doesnt climb in rpm or speed. The engine revs like it Wants to but it doesnt. This is around 4th gear or so. But when im driving normally it can go through all the gears just fine? Im hoping its not the entire trans! I pulled fuse 29 and 31 but it didnt do the trick. So Im thinking maybe coil packs or spark plugs? Even fluid change IDK. But I figured id come here first to see if it had happened to anyone else. Of course a google search shows nothing similar lol. Thank you!
 

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2015 R/T 5.7L A8
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Check your intake manifold bolts to see if they are loose, it is a common issue with the plastic intake manifolds on the 5.7 and the 6.4

Sharing Regarding the 5.7L Intake Manifold

If your bolts are not loose, which I seriously doubt, try doing the throttle re-calibration.

Get in the drivers seat, do not press the brake, press start 2 times to go to the run position, wait for all the dash lights to remain stable, slowly press the accelerator pedal to the floor and hold it on the floor for at least 20 seconds, (this tells the ECM Engine Control Module that you are re-calibrating the throttle position), after 20 seconds slowly let off of the accelerator pedal and take your foot off. Now start the car normally and see if it made a difference.
 
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I also did the "fuse pull" for the ECM, and that really makes a difference.
It's now a bi-weekly thing for me to do, especially after the wife drives it for a while.
 

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Try a battery disconnect for a minute or so. Sometimes need to reboot these things like a computer o_O
 

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Try a battery disconnect for a minute or so. Sometimes need to reboot these things like a computer o_O
I think the battery disconnect will also wipe out other settings, like radio presets, steering mode, center display layout, etc.
That why I just pull the fuse for 20 mins, to let it drain and reset, but leaves the rest of the car alone.
 

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Discussion Starter · #8 ·
Check your intake manifold bolts to see if they are loose, it is a common issue with the plastic intake manifolds on the 5.7 and the 6.4

Sharing Regarding the 5.7L Intake Manifold

If your bolts are not loose, which I seriously doubt, try doing the throttle re-calibration.

Get in the drivers seat, do not press the brake, press start 2 times to go to the run position, wait for all the dash lights to remain stable, slowly press the accelerator pedal to the floor and hold it on the floor for at least 20 seconds, (this tells the ECM Engine Control Module that you are re-calibrating the throttle position), after 20 seconds slowly let off of the accelerator pedal and take your foot off. Now start the car normally and see if it made a difference.
Awesome thank you! I'll try both of these when I get home from work in a couple hours. Would that also maybe explain the slight "thumping" sound /feel in the engine? At idle I notice it
 

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Discussion Starter · #9 ·
I think the battery disconnect will also wipe out other settings, like radio presets, steering mode, center display layout, etc.
That why I just pull the fuse for 20 mins, to let it drain and reset, but leaves the rest of the car alone.
Check your intake manifold bolts to see if they are loose, it is a common issue with the plastic intake manifolds on the 5.7 and the 6.4

Sharing Regarding the 5.7L Intake Manifold

If your bolts are not loose, which I seriously doubt, try doing the throttle re-calibration.

Get in the drivers seat, do not press the brake, press start 2 times to go to the run position, wait for all the dash lights to remain stable, slowly press the accelerator pedal to the floor and hold it on the floor for at least 20 seconds, (this tells the ECM Engine Control Module that you are re-calibrating the throttle position), after 20 seconds slowly let off of the accelerator pedal and take your foot off. Now start the car normally and see if it made a difference.
Okay I just finished these. I'll post an update when im at work tomorrow. Fingers crossed!🤞🏽
 

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Discussion Starter · #10 ·
Check your intake manifold bolts to see if they are loose, it is a common issue with the plastic intake manifolds on the 5.7 and the 6.4

Sharing Regarding the 5.7L Intake Manifold

If your bolts are not loose, which I seriously doubt, try doing the throttle re-calibration.

Get in the drivers seat, do not press the brake, press start 2 times to go to the run position, wait for all the dash lights to remain stable, slowly press the accelerator pedal to the floor and hold it on the floor for at least 20 seconds, (this tells the ECM Engine Control Module that you are re-calibrating the throttle position), after 20 seconds slowly let off of the accelerator pedal and take your foot off. Now start the car normally and see if it made a difference.
Well of course with my luck it's NEVER just a simple fix. Nothing happened, although the bolts were actually pretty loose especially bolt 6 but its still doing it and at this point I have no clue. I took it to a shop and they couldn't find anything wrong not even with the spark plugs and coil packs. They said id have to take it to Dodge (which I wanted to avoid doing) since I guess it might be something with the timing systems or idk but yea I guess im gonna have to call them. They just over charge for EVERYTHING though
 

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2015 R/T 5.7L A8
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Well of course with my luck it's NEVER just a simple fix. Nothing happened, although the bolts were actually pretty loose especially bolt 6 but its still doing it and at this point I have no clue. I took it to a shop and they couldn't find anything wrong not even with the spark plugs and coil packs. They said id have to take it to Dodge (which I wanted to avoid doing) since I guess it might be something with the timing systems or idk but yea I guess im gonna have to call them. They just over charge for EVERYTHING though
Have you run your own diagnostics on it?

I bought a Blue Driver https://www.amazon.com/BlueDriver-B...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== and it has saved me a lot of concern when a check engine light goes on as to whether it is an instant issue or one that can wait to be fixed, it will also show you codes that have been deleted in case of the car being previously owned. You probably already have a diagnostic tool this plugs into the OBD2 port and reads through an app on your Android or Iphone, helps to know exactly what is wrong, especially if you have to go to a dealers service department they cannot exploit the problem. Also there are many things wrong that you can fix yourself.

Simple: Possibly Water in your gas tank, add some fuel line drier to remove it.

Dirty fuel injectors, try https://shop.advanceautoparts.com/p...ystem-cleaner-and-stabilizer-11722/10881745-P
I am a firm believer in this product, I use it myself, and it did make a difference.

You could have a bad knock sensor?
 

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Discussion Starter · #12 ·
Have you run your own diagnostics on it?

I bought a Blue Driver https://www.amazon.com/BlueDriver-B...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== and it has saved me a lot of concern when a check engine light goes on as to whether it is an instant issue or one that can wait to be fixed, it will also show you codes that have been deleted in case of the car being previously owned. You probably already have a diagnostic tool this plugs into the OBD2 port and reads through an app on your Android or Iphone, helps to know exactly what is wrong, especially if you have to go to a dealers service department they cannot exploit the problem. Also there are many things wrong that you can fix yourself.

Simple: Possibly Water in your gas tank, add some fuel line drier to remove it.

Dirty fuel injectors, try https://shop.advanceautoparts.com/p...ystem-cleaner-and-stabilizer-11722/10881745-P
I am a firm believer in this product, I use it myself, and it did make a difference.

You could have a bad knock sensor?
Well I probably should have mentioned there is actually no check engine light. And when the shop checked everything and hooked it up to their checker Nothing came up and all seemed to be fine. So I'm not sure at all but It idles rough and I can hear a thumping sound almost like something turning? Idk how to explain it
 

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Discussion Starter · #13 ·
Have you run your own diagnostics on it?

I bought a Blue Driver https://www.amazon.com/BlueDriver-B...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== and it has saved me a lot of concern when a check engine light goes on as to whether it is an instant issue or one that can wait to be fixed, it will also show you codes that have been deleted in case of the car being previously owned. You probably already have a diagnostic tool this plugs into the OBD2 port and reads through an app on your Android or Iphone, helps to know exactly what is wrong, especially if you have to go to a dealers service department they cannot exploit the problem. Also there are many things wrong that you can fix yourself.

Simple: Possibly Water in your gas tank, add some fuel line drier to remove it.

Dirty fuel injectors, try Advance Auto Parts - Down for Maintenance
I am a firm believer in this product, I use it myself, and it did make a difference.

You could have a bad knock sensor?
Ok I just got the Royal Purple stuff and I'm gonna try and empty my tank a good amount before putting it in. Fingers crossed again haha🤞🏽
 

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2015 R/T 5.7L A8
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So I'm not sure at all but It idles rough and I can hear a thumping sound almost like something turning? Idk how to explain it
You're hearing a thumping sound, from where?

Just to be on the safe side check the center support bearing of your driveshaft, if it has torn loose it could be wedging itself, when it tears loose it looks like this.

Plant Bumper Automotive tire Wood Grass


Your 392 has exactly the same driveshaft as the 5.7, this was mine and it was flopping around like a fish out of water, power robbing and dangerous, check it to be sure.
 

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Discussion Starter · #15 ·
You're hearing a thumping sound, from where?

Just to be on the safe side check the center support bearing of your driveshaft, if it has torn loose it could be wedging itself, when it tears loose it looks like this.

View attachment 287812

Your 392 has exactly the same driveshaft as the 5.7, this was mine and it was flopping around like a fish out of water, power robbing and dangerous, check it to be sure.
Ok I'll check when I get home, and that little thump is coming from the engine it feels like. When im driving I can hear/feel it infront of me so it has to be something up front I think. I felt that thump a while back but its just Now robbing power and causing it to freak. Idk if they are directly related
 

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Discussion Starter · #16 ·
You're hearing a thumping sound, from where?

Just to be on the safe side check the center support bearing of your driveshaft, if it has torn loose it could be wedging itself, when it tears loose it looks like this.

View attachment 287812

Your 392 has exactly the same driveshaft as the 5.7, this was mine and it was flopping around like a fish out of water, power robbing and dangerous, check it to be sure.
Wow so right now leaving a restaurant my car barely started! Ugh im thinkin its getting bad fast whatever it is
 

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2020 Dodge Challenger Hellraisin Scat Pack
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Wow so right now leaving a restaurant my car barely started! Ugh im thinkin its getting bad fast whatever it is
The behavior regarding acceleration and barely starting suggests a problem with the fuel system. Not too far fetched to believe the thumping may be fuel system (fuel pump?) related rather than driveshaft related. But the driveshaft being the source of the thumping needs to be confirmed/eliminated.
 

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2016 SRT 392 Challenger MBRP exhaust, Jay Greene tune, K and N intake, aluminum drive shaft, 95 mm t
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I had the problem with the center bearing on the drive shaft with mine it was a constant thumping sound. If it only thumps every once in a while you probably have something going on with your fuel system. Also I know it sounds dumb but have you checked your air filter it can make your car run rough
 
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Discussion Starter · #19 ·
You're hearing a thumping sound, from where?

Just to be on the safe side check the center support bearing of your driveshaft, if it has torn loose it could be wedging itself, when it tears loose it looks like this.

View attachment 287812

Your 392 has exactly the same driveshaft as the 5.7, this was mine and it was flopping around like a fish out of water, power robbing and dangerous, check it to be sure.
Update I checked under and everything seems fine. I actually got a P0171 code last night and I assumed it was a loose 02 sensor (I used to be catless so I was used to seeing that code and re tightening them) but upon checking they were tight. And the driveshaft was okay too. So I read up and took out my CAI to clean it and it was FILTHY! I had forgot to mention a few weeks ago on the way to work a car infront of me merged to the side a bit which threw a CRAP load of dirt to the front end of my car and im assuming it went straight to the filter. It started acting weird almost immediately after that, I felt a difference right after. Anyways I cleaned it and all that mud/buildup so lets hope that does the trick. And I also did the battery disconnect. I can hear the slight thumping in the engine still and I can try and get a sound clip later. It might be too subtle to catch but lets hope all goes well. Oh and I have a K&N Typhoon
 

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Discussion Starter · #20 ·
Have you run your own diagnostics on it?

I bought a Blue Driver https://www.amazon.com/BlueDriver-B...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== and it has saved me a lot of concern when a check engine light goes on as to whether it is an instant issue or one that can wait to be fixed, it will also show you codes that have been deleted in case of the car being previously owned. You probably already have a diagnostic tool this plugs into the OBD2 port and reads through an app on your Android or Iphone, helps to know exactly what is wrong, especially if you have to go to a dealers service department they cannot exploit the problem. Also there are many things wrong that you can fix yourself.

Simple: Possibly Water in your gas tank, add some fuel line drier to remove it.

Dirty fuel injectors, try Advance Auto Parts - Down for Maintenance
I am a firm believer in this product, I use it myself, and it did make a difference.

You could have a bad knock sensor?
Also I should add, the light came on right after putting the royal purple in. Related? Who knows but lets hope all is well, im currently at work and It definitely is shifting Way smoother! Haven't stepped on it yet but I will later on
 
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