RPM Dip/bounce when letting off throttle

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May 11, 2023 | 05:49 PM
  #1  
I took two new logs today. I have a bit of an exhaust leak from my test pipes where they mate from the manifold, so I think that explains the small amount of high fuel trims that I see strictly when im idling. When moving, the fuel trims look good, and my long terms are right around 10, so im not running crazy lean either. Anyways, the first log just shows the car after startup hunting for idle, but it never finds it. It does this almost every time its started up and not still close to operating temp. The rpms go up, come down, kind of with a mind of their own, all within a few hundred RPM. The second log (you can tell the first log from the second log because the headers will appear again) shows a drive where I was intentionally trying to get the RPM dip to occur. To describe the dip, It usually happens when im cruising in a higher gear, so lower rpm, and a low ish speed. If I remove my foot completely from the gas, instead of the RPMs slowly returning down to idle speed, they fall quickly down below idle speed, and then just as quickly as they fell, they jump back up. It makes the car lurch forwards, and makes coming to a stop very uncomfortable. I think if you look at throttle position up against RPM, you will see me remove my foot from the throttle, and the the rpms dip down and then jump back up. Ive been chasing this for a while and haven't been able to find any correlations. I included a lot of PIDS in the excel file because Im not exactly sure what the issue is, so feel free to delete any columns you don't find necessary or alter the file in any way you need.




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May 18, 2023 | 11:02 PM
  #2  
I have been having the same problem.... does it do that in park too?
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May 19, 2023 | 12:36 PM
  #3  
Quote: I have been having the same problem.... does it do that in park too?
can't seem to find idle in park sometimes
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