Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

MK4 Supra Automatic Tuning

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


Hey guys Im currently working on a MK4 with a stock auto, I have the car running pretty well. My issue is that Im having trouble with the auto transmission map at WOT. All of the other shift points during normal driving and cruise are perfect, but down shifting during a roll race is terrible in both the auto and manual modes. Tuning on a AEM series II ems. Still trying to learn here so any help would be greatly appreciated!

What exactly do you mean by "terrible"?. Is it just taking too long to initiate the downshift?... or is there a problem with the shift itself?

Sorry for lack of detail it was a bit late for me when I was typing this out. Basically the car wont shift in manual mode and it takes far too long to shift down. Shifts are nice an firm when you punch it. But trying to brake boost to race from a roll it wont shift down and hold gear. If you put it in manual mode it wants to try and skip gears

I still don't know what you're saying... but it sounds like it could be a mechanical fault.

So for example in manual mode it goes from 1st straight to.third when you put it in second. In auto mode when trying to brake boost say from rolling in 4th cant get it to shift to 2nd. This is all from a roll. Not doing any dig runs as he is still on stock auto.

Without having any direct experience with these automatic transmissions, I'd tend to agree with Marek based on your description - It sounds like there may be a mechanical fault with the transmission.

Andre if I attach my map on here do you think you might be willing to look at it and give me some pointers. The mk4 supra trans is a finicky beast on the aem ems

You may look at the firmware on the AEM. There is a history of AEM and Supra Autos not playing well together.


I'm happy to look but I've got zero experience with the AEM on an automatic supra so I'm not sure how much help I'll be able to offer.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?