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2010 R/T Classic 392 cam,LT headers, full exhaust, K&N CAI, and a few others
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Discussion Starter #1
  1. As the title stated ever since I got my 392 cam in my car after about a month or so the car gradually runs rough especially on cold starts (and even warms starts but especially cold) the part that makes no sense to me is if I simply reload the EXACT same tune I've been running the car will run perfectly again until weeks later it starts doing the same thing again. First a little rpm drop on cold starts which turns into eventual stalls on cold starts within another week or two.
 

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probably get a better tune for it.

I haven't heard of the performance degrading as time goes by.

Proper tuning also addresses driveability, idle quality, and how the power output / curve is developed.

(edit) - I'd also check to make sure there's no vacuum leaks and intake manifold bolts are torqued down (they're known to loosen up at times) its 105in.lb. / 8.75 ft.lb.
 

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Hal H offered some good comments.

For curiosity's sake erase error codes with an OBD2 code reader/data viewer. Even though there are no codes (and the CEL is dark) this (should for it does this with the stock "tune") reset all the learned behavior to their factory defaults.

(Yeah, rather than using an OBD2 code reader you could disconnect the battery for a bit but I just abhor messing with the battery like that. An OBD2 code reader should be in your tool box anyhow.)

If the engine runs better -- as it does after a reflash of the tune -- this suggests the tune modifications are interfering with the rest of the engine controller program that adapts/learns.
 

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Sounds like you have a “canned” email tune. Find a good performance shop with a chassis dyno and MOPAR experience. She’ll be running like a top in no time. Where do you live?
 

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2010 R/T Classic 392 cam,LT headers, full exhaust, K&N CAI, and a few others
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Discussion Starter #6
Sounds like you have a “canned” email tune. Find a good performance shop with a chassis dyno and MOPAR experience. She’ll be running like a top in no time. Where do you live?
I'm from Nj, and yea it's an email tune. I'm waiting for funds for a nitrous kit before I take it for a real dyno tune.
 

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2010 R/T Classic 392 cam,LT headers, full exhaust, K&N CAI, and a few others
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74 Posts
Discussion Starter #7
Hal H offered some good comments.

For curiosity's sake erase error codes with an OBD2 code reader/data viewer. Even though there are no codes (and the CEL is dark) this (should for it does this with the stock "tune") reset all the learned behavior to their factory defaults.

(Yeah, rather than using an OBD2 code reader you could disconnect the battery for a bit but I just abhor messing with the battery like that. An OBD2 code reader should be in your tool box anyhow.)

If the engine runs better -- as it does after a reflash of the tune -- this suggests the tune modifications are interfering with the rest of the engine controller program that adapts/learns.
I tried clearing codes because I do have codes for the rear o2s that are hidden since I'm catless and that didn't do anything. I also tried the battery disconnect once but I definitely didn't disconnect it long enough which is why it didn't do anything. And I checked intake manifold bolts as well they were a little loose but after I retightened there was no effect even after days. My only theory is something to do with the "learning" of the computer somehow working backwards and making it run worse cuz if I really wait long before reloading the tune it starts to let out some black smoke when I stop at red lights as if A/F is off or something. Thanks for all the great replies btw I'll keep this thread updated if I find a solution.
 

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The next time it starts running rough, try the old fuse pull to get rid of learned driving / operating info..just to see.. I've done that to mine and it does freshen up my ride.. It might be confused, throwing codes, engine trying to compensate, then with it not running correctly becomes compounded.. I would say high flo catted midpipes, if it's running rich, lean it out incrementally..Your good running car is in there waiting.. I'm a 2014 R/T, fuse # 2, leave out 10 min? Put back in, does not affect your tune. Your fuse may be a different one, but if it clears and runs better then it's a progressive, learned function..
my humble opinion.. ; )
 

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Here's a link to some other discussion
 
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