(UNSOLVED) Lund Flex/E-85R Tune Not Decellerating 2019 PP2

[Sheenapple]

looking for some help or ideas. i'm running Lunds flex tune on my 2019 PP2 with drop in K&N, borla atak, and 170 tstat. since the first baseline 93 tune the car it has started to not decelerate when i pull my foot off the gas after taking it over a certain RPM and throttle position. normal driving/cruising it decelerates as it should. this is seperate from the normal rev hang issue. this occurs on the 93 tune, flex, and e-85r tune, as far as i can remember this did not occur on the stock tune. i have to go back and re-test stock once i run this tank down. Lund has said this is my issue and that the logs look fine.

historical info:
when running the e-85r tune in heavy traffic the fuel pump died last friday, no warning. flashed the flex tune and replaced the pump yesterday and the car is back to running. still has the deceleration issue
14.4k miles
when i bought the car new (around 200 miles), it died on the middle of the freeway and went into limp mode. when i got home i cleared the codes, pulled the battery, pulled the MAF and cleaned it. put it back together and no issues since.
car has half a tank of 93/e-85 mix now and is on the flex tune
emissions monitors are not set (not sure if it matters)

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[moderatespender]

Mine does the same thing no longer rev matches after tune. They told me to do a tran relearn.

 

[Sheenapple]

attached are the data logs. on the 4.26.2020 Flex Rev Hang Issue.xlsx log. around row 874. from there on the pedal position is 0 (foot off of pedal) but the AFR1 & AFR2 do not snap shut to 2 like it should. this is when the issue is present. later on in the log on exactly row 2559 the decel start working as it should. AFR1 & AFR2 are snapping to 2 when pedal position is 0, this shows decel is actually occuring.

you can filter the log by pedal = 0 and anywhere where the log has large amounts of rows where AFR1/2 is not 2 or climbing to 2 is the issue

 

[Sheenapple]

so lund gave me a revised test tune which appears to be the stock tune but with e-85 fueling mapped to it. the issue is solved. so i'm continuing to work with Lund to see if i can get a flex version of this with proper spark/timing adv and a e85r version of this with the usual mappings.

logs are attached, Test Tune log is where the issue is fixed. e-85r decel issue log is where it is broken

 

[moderatespender]

Good i will contact Lund. They told me to do a reset on trans and it didn't work. Also getting trans fluid checked.

 

[Sheenapple]

what type of car do you have? sounds like a 2018 mustang gt with a10? not familiar with a "reset on trans" for a manual car.. if your car is auto, i likely wont be able to help with anything i learn from my scenario

 

[moderatespender]

what type of car do you have? sounds like a 2018 mustang gt with a10? not familiar with a "reset on trans" for a manual car.. if your car is auto, i likely wont be able to help with anything i learn from my scenario

Oh yeah mine is a 18 auto

 

[Sheenapple]

on the stock tune do you have any issues? that was my biggest comparison is logging stock vs lund back to back and highlighting the issue in the log for them

 

[2018GT]

This won’t help you in any way, but if the stock tune works and the Lund tune does not.. then I don’t understand how it is the car.

The variable that changes is the tune which affects the car working well or not working well. I’m definitely not a tuner nor have I ever dealt with one for the mustang, but that seems like simple logic to me.

if there is something wrong with the car the Ford tune is handling it better it seems.

 

[Sheenapple]

update 8/8/2022:
This was never solved and I’ve been running the stock tune since

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