Halo,
There is no reason whatsoever taht an Auto 4A-GE should be sluggish by design. I myself is currently driving an even older 4A-GE 20V Auto Silvertop and there is no such thing as sluggishness.
So what could be the problem? let's see. I suspect that some sensors are not reading properly, the most common ones are O2 Sensor which is connected to the exhaust header. If the ECU is not getting any proper reading from the sensor it will run in safe mode where ignition timing will be retarded a lot - once retarded engine will be super sluggish and farts black smokes occasionally.
The other one is speed sensor as 4AGZE mentioned. If the speed sensor is not connected properly to the Speedo Meter you will get the same symptom, runing in Safe Mode again. To know if speed sensor is not connected properly - all you have to do is set your gear to N and rev all the way to the Rev Limiter, it should be able to clock 8200RPM as shown on the Denso Speedometer. If it cuts below 7000RPM then you can confirm the problem.
How to know if you are running in safe mode? did u see any check-light on your dash blinks occassionally during driving? Or what u can do is go to a mechanic which is familiar with Toyota diagnostic tools and ask them to do it. I recommend TRIAL Tuning Spirit in Sg. Besi or United Motor in Sunway.
Or, are u sure your ECT-S is able to run in Power Mode? Running Auto 4A-GE in Manual Mode will make it sluggish too.
Ignition Timing, the most common problem is simply that ignition timing is set too low. A healhy 4A-GE should be running a minimum of 11 Degree of Advance Timing. Again this can be checked by a mechanic.
Hope this helps
