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Discussion Starter #1 (Edited)
Hi everyone. I have a 2011 R/T, 6 speed with a cold air intake, Diablo91 tune with +20 throttle boost, and a resonator delete. 24k miles.

I have been noticing a very slight shaky idle the last few weeks. Nothing drastic, just like a light vibration coming from under the driver seat.

I got stuck on the side of the highway last week. The gas pedal was not responsive, almost like it was disconnected. I was able to coast to the side of the road and shut the car off. I was able to restart it, but it made a horrible grinding noise and would only crawl forward. The guy at the repair shop said the throttle body needed to be replaced, which he did. He said the tune would not have had anything to do with it, and that the part likely failed due to age or it was defective, or both.

This morning I noticed that the clock was off by several hours. This afternoon the car did something similar to last week when I got stranded, except this time when I restarted it, it was fine. I plugged my tuner in and there was a code, P2601 Throttle Actuator Control System.

Any idea why I'm still having problems, even with the new throttle body? I was thinking maybe the battery is failing? I bought the car two years ago, but I believe the battery is original. The first two digits on the heat stamp are 1F, presumably June 2011. Battery voltage is reading between 12.3 and 12.8 Key fob sometimes doesn’t work.

I think the battery needs to be replaced regardless because of its age. If that doesn’t do the job, maybe it’s an electrical wiring issue? I wouldn’t doubt that my underground parking has rodents. Haven’t seen evidence of them in or under the car, but who knows what might have chewed on something.
 

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2018 Scat Pack SHAKER in Plum Crazy
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Was the clock of by "a couple of hours" or "exactly x hours" if so, it probably lost what time zone the GPS setting was based on and might even self correct based on settings.
Is it the original battery? If so, definitely start there.
 

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You think the code was never cleared after the shop replaced the throttle body? Also do you know if they did the throttle relearn? BTW 2011s had some recalls...like WIN module, timing chain tensioner and I think alternator.

Type your vin here to see if you have any open recalls first.

If you have none then I would start by doing a throttle relearn. There is software called alfaOBD ($50 and comes in android or PC version) that can do this and much more. Also needs an OBD interface...obdlink brand is known ot work without issue.

If you are experiencing a rough idle you might have what happened to my 2015 where VVT is oscillating (this can be viewed by logging exhaust actual cam position). In my case the stock tune had VVT kicking in a 600 rpm with engine oil still fairly cold which caused the cam to oscillate. Bumped the values up to a 2015 6.4 and all is good (this can't be done with diablo but can be done with HP tuners).

Also check your intake manifold bolts for proper torque. Then tend to loosen over time.
 

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Discussion Starter #4
Was the clock of by "a couple of hours" or "exactly x hours" if so, it probably lost what time zone the GPS setting was based on and might even self correct based on settings.
Is it the original battery? If so, definitely start there.
Three hours fast. I assume the battery is original given the code stamped on it.

You think the code was never cleared after the shop replaced the throttle body? Also do you know if they did the throttle relearn? BTW 2011s had some recalls...like WIN module, timing chain tensioner and I think alternator.

Type your vin here to see if you have any open recalls first.

If you have none then I would start by doing a throttle relearn. There is software called alfaOBD ($50 and comes in android or PC version) that can do this and much more. Also needs an OBD interface...obdlink brand is known ot work without issue.

If you are experiencing a rough idle you might have what happened to my 2015 where VVT is oscillating (this can be viewed by logging exhaust actual cam position). In my case the stock tune had VVT kicking in a 600 rpm with engine oil still fairly cold which caused the cam to oscillate. Bumped the values up to a 2015 6.4 and all is good (this can't be done with diablo but can be done with HP tuners).

Also check your intake manifold bolts for proper torque. Then tend to loosen over time.
Totally possible the code wasn’t reset at the shop. Thanks for the tip on the recall. When I entered my vin it said the alternator had a recall in 2017. It says the repair was made.

I will also look at logging the data you suggest to see if that is happening.

Could the spark plugs be contributing to the rough idle? I assume that would have nothing to do with the throttle body issue. But the manual says to change them at 30k miles and it’s getting close to that.
 

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Three hours fast. I assume the battery is original given the code stamped on it.



Totally possible the code wasn’t reset at the shop. Thanks for the tip on the recall. When I entered my vin it said the alternator had a recall in 2017. It says the repair was made.

I will also look at logging the data you suggest to see if that is happening.

Could the spark plugs be contributing to the rough idle? I assume that would have nothing to do with the throttle body issue. But the manual says to change them at 30k miles and it’s getting close to that.
Regarding plugs being related to the rough idle. This is definitly a maybe. Does the engine manifest any issues above idle, at steady speed cruising at various speeds, under hard acceleration?

If not plugs probably not responsible for the behavior. However, the plugs are close to their replace by date. Might consider killing two birds with one stone and have the plugs replaced now. You get the plug service out of the way and you learn whether or not the old plugs played any role in the engine's rough idle.
 

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Honestly I have a JGC with the copper plugs and have had more than 40k on a set and no difference in idle or driveability that I could detect. Now on my 2015 RT the manifold bolt were loose and took more than 2 turns to get to proper torque. Once tightened I immediately noticed a difference in idle and throttle responce.
 

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Honestly I have a JGC with the copper plugs and have had more than 40k on a set and no difference in idle or driveability that I could detect. Now on my 2015 RT the manifold bolt were loose and took more than 2 turns to get to proper torque. Once tightened I immediately noticed a difference in idle and throttle responce.
Agree the plugs are not likely to be the source of the idle behavior. Not sure if the OP has a car that develops loose manifold bolts but if he does those certainly should be checked first.

As a general rule I prefer to when trying to eliminate possible causes of a problem to unless there is a glaring sign of what the problem or the problem is common enough the cause is known even if not obvious to the average person is to do simpler/less expensive things first. But reasonable things. Better is if these things are based on reports often the source of the problem so much the better. I mean I would not check tire air pressure for a rough idle even if it is simple/easy to do. In this case of the rough idle changing the plugs would come after checking the manifold bolts and in this case because they are close to being due to being changed.
 

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Discussion Starter #8 (Edited)
Probably a dumb question, but is tightening the manifold bolts something they would already have done when the throttle body was replaced? Like would they have had to remove it in order to get to the throttle body?

I had the oil changed a couple months ago and had them inspect the plugs because I knew the recommended life on them was getting close. They didn’t think it was urgent to replace. They also wanted like $700 to replace them. Gap was 1.12 instead of 1 mm.
997780
 

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Replacing throttle body does not require removal of the intake so no, the intake bolts will not be touched...just the 4 throttle body bolts.
 

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I am not a fan of removing plugs to inspect them unless there is good evidence the plugs are at fault or will have something interesting and helpful to say. You have not even seen a CEL so the plugs are not that high on the suspected causes list.

The plugs get pulled and read to learn what if anything they have to say. Then I install new plugs. I do not like to remove used plugs then install them again. I don't know if this is the case with Dodge plugs but with plugs for other brands of cars the factory plug threads come with a special finish/coating that is intended to act as a thread lubricant to ensure accurate torquing. But this is a one time thing. Anti-seize is not a suitable alternative.

That the plugs were apparently reinstalled with the 1.12mm gap vs. the correct 1.0mm gap just adds insult to injury.
 

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Discussion Starter #11
I was trying to make sure the bolts were properly torqued. The first bolt all the way to the front on the passenger side cracked off. The torque wrench didn’t click so I kept turning. The threaded, bottom part of the bolt is still stuck in the hole.

Do I have to have the bolt replaced or can it just be left like that? Seems pretty secure.
 

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I was trying to make sure the bolts were properly torqued. The first bolt all the way to the front on the passenger side cracked off. The torque wrench didn’t click so I kept turning. The threaded, bottom part of the bolt is still stuck in the hole.

Do I have to have the bolt replaced or can it just be left like that? Seems pretty secure.
If the bolt head snapped off the remaining portion of the bolt may be secure -- tight -- but is not applying any holding force to the part. The part is not being properly held down. If this is in reference to -- and think it is -- something like an intake manifold, it is important all bolts contribute an equal and correct hold down force.

In short then the remaining bolt fragment needs to be removed and and new bolt obtained and installed and torqued correctly. The tech will remove the old bolt and ensure the hole and its threads are ok and that new bolt threads into the hole deep enough to not bind/jam in the hole before it can tighten down and clamp the part properly.
 

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Discussion Starter #13
I’m planning to bring it in tomorrow. It’s actually the exhaust manifold, not the intake manifold (which is what I thought I was tightening, but no). I won’t be doing any more work on the car. I’ll leave it to the professionals lol.

If I leave that one bolt off the exhaust manifold, what would actually happen? An exhaust leak? Wouldn’t I get a check engine light and/or be able to hear it?
In other words, can I leave it until/when/if something happens? Or will it be doing damage to the car?
 

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I’m planning to bring it in tomorrow. It’s actually the exhaust manifold, not the intake manifold (which is what I thought I was tightening, but no). I won’t be doing any more work on the car. I’ll leave it to the professionals lol.

If I leave that one bolt off the exhaust manifold, what would actually happen? An exhaust leak? Wouldn’t I get a check engine light and/or be able to hear it?
In other words, can I leave it until/when/if something happens? Or will it be doing damage to the car?
The risk of an exhaust leak is it messes up the O2 sensor reading. This can lead to less precise fueling. This is not good.

Another risk is the leak over time can erode the surface against which the manifold bolts to and to which it must seal and maintain this seal under extreme conditions. With this erosion that may not be possible.

Last is the exhaust leak puts hot exhaust gases in the engine compartment. This can subject critical engine and engine compartment hardware, fuel lines, wiring, etc. to hot (and corrosive) exhaust gases.

My advice would be to the broken bolt fixed and the exhaust manifold properly bolted to the head and with no leaks.
 
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