[RichardJ]

Hi guys, I have a 2015 AT and I am having severe transmission issues. I would appreciate some help.

Current mods I have is Weir's 4.88 fd, jdl catless uel, catback and OFT stage 2 tune.

I had a track today and it confirms my transmission or tune is 100% fucked.

Ever since getting Weir's 4.88 fd installed I've been having some issues with the tranny and possibly the ECU/tune.

Transmission Issue:
First, the issue is mainly for first, second and third gears. During regular city driving, when switching back and forth between manual mode and auto, the car would sometimes rev freely when I gas it as if it is in neutral. The gears would not be engaged, and sometimes redline if I gas it hard. Sometimes it does shift but it feels like power is cut majorly.

Turning the car off and restarting it temporary fixes the issue.
Also, when I downshift into any of these gears and rpm is at like 4k rpm, it suddenly drops down to 1k and revs freely like I previously described.

It is similar to this guy but mine drops completely to 1k rpm:
[ame="https://www.youtube.com/watch?v=hBZQbFU2s-g"]Scion FRS Transmission Issues - YouTube[/ame]

I have not experienced this with the taller gears in the highway (4-6).

This issue has been apparent and continuing since installing the gears one month ago. The fluid has been changed during installation.

When the car is working it feels great. Pulls very nicely and strongly and I enjoy it when it does not have these issues.


ECU/Tune:
I logged for the first time since I got the headers installed and tuned with OTS stage 2 tune with JDL tables I found somewhere in the forum. The only other changes is a quiet cold start and AT throttle map from Wayno.
I have not switched tunes after installing gears.

I remember logging many times after flashing with the stage 2 tune and concluding it was running fine. IAM at 1, no major FLKC, under 4% fuel trims.

Today I logged on the highway after experiencing transmission issues around town, and the IAM was between 0.54-0.9. Non-zero values of FLKC (usually below -1) and KC learned. Fuel trims were +6% sometimes. I fueled up with Shell like always before hitting the highway. It sounds like a really shitty batch of fuel but I didn't know it would be that bad. I was almost at the track by the time I logged this, so I didn't turn around and went to the track.

At the track the car managed 1 clean lap with no issues in automatic mode. 2 more as a complete shit show the moment I tried to change gears myself.
Same tranny issues and major cut in power throughout the higher rev range. I had to stop as the car did not run properly at all.

On my way home I babied it and left it in automatic. Did not experience free-revving issue but I can feel a lack of torque and power in the lower range just driving around town.

I am not sure what the issue is. I feel like the tune issue is just for today with the very shitty batch of fuel. The transmission issue has been happening very often.

Any ideas on how to approach these problems??

***UPDATE***
Emptied the god awful remainder of Shell 91 gas and fueled up with Esso 93.
Data logged and IAM is back to full time 1 and non-existent FLKC.
Haven't pushed it yet but I fear the tranny issues may return. No transmission issues since battery reset though.