2008 Acura TL Type-S — transmission won’t upshift under hard acceleration
I have a 2008 Acura TL Type-S automatic with 326,000 km. Under hard acceleration in regular Drive, when I floor the gas pedal, the engine revs to around 5,500 RPM but doesn’t shift into the next gear until I let off the gas. It will bounce like that and stay at high RPM until I ease off the accelerator and then it’ll shift. It only happens when putting heavy acceleration not normal driving. The + paddle shifters work tho
I was told the transmission had been replaced around 150,000km but I cant confirm.
Acura dealership initially thought transmission pressure switches because a technician had fixed a similar issue on his 2004 TL by replacing them. After road testing they thought the PCM/engine computer, suggesting an incorrect tune or calibration, even though my car has never been tuned. But they didn’t really know
Earlier this year, the PCM firmware was updated to deal with an existing electrical issue. Acura redownloaded the latest firmware but it made no difference to the shifting problem.
My check engine light is almost always on for a P0420 code—catalytic converter not heating up to the right temp.
Has anyone experienced this on their TL? Could it be my catalytic converter’s? I also have an oil leak from my oil pump but my oil level and my transmission fluid checked out.
Where would you start with this issue?
TLDR:
2008 TL Type-S automatic, 326,000 km. Under full throttle in Drive, it revs to ~ 5,500 RPM and won’t upshift until I let off the gas, but the + paddle shifter works normally. Transmission was allegedly replaced at 150,000 km. Acura initially considered pressure switches but later suspected the PCM/engine computer, possibly an incorrect tune or calibration, despite the car never having been tuned. They redownloaded the latest PCM firmware, but it didn’t fix the issue. Looking for ideas on what to do next.