posting in the engine forum because the trans tune is stock
i recently changed the [ECM] 44681 Spark Minimum Torque Reduction table and set much of the table to 7 deg, previously it had values from -39 to 7. after this change i often get a stumble during the 2-3 upshift. i attached a log file (and tune), at the 8:11:52 mark you can see an example.
maybe my change to the table was too much, and i need to put back some of the spark reduction?
is there a method to address this another way?
vehicle is a stock durango rt 5.7 8HP70, only mod is SOS coils and the larger plug gap
I'd suspect the stumble is related to an ignition misfire as indicated by a massive lean spike shown on the log as the large shift in Short term fuel trims of about 20%. STFT jump from slightly too rich about -5% all the way to +16%, but only for a brief instant.
Log Misfire counts to verify.
Knowing that you touched the plugs and coils is verification that it is probably a misfire.
i reset adaptives incl fuel trims after i made the change so maybe that lean spike is temporary as the trims systems does its thing over a few drive cycles?
i've been tinkering with this car and its tune for a couple years and i've always had this issue at 2-3 after changing this particular 44681 Spark Minimum Torque Reduction table. only now i decided to message the forum. sort of nice to see someone else witness a similar thing.
out of curiosity i updated that same table changing the 7 deg cells to 0 (and reset adaptives again) and so far i am not experiencing that 2-3 shift stumble. and i did log for misfires and there were some, mainly at startup. no engine light on dash so i guess not enough misfires to worry? anywhere from 1 to 6 misfires. logs attached.
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