Can someone figure out why my Vitz 04 Auto changes gears normally till 3, afterwards just on 5-6km/h more it shifts to 4th and car becomes too heavy n pickup dies.
And on OD(Over-drive) after 3rd it shifts to 4th at 73-75+ km/h even if release n press the accelerator for a shift.Car keeps shouting 
Another problem im facing is tht whn the car is parked and shifted to D mode with AC on, car RPM goes up n down every second, not allowing the AC compressor to work.
My CAT is removed, while doing tht i saw another "dholki" in the pipe between CAT one and silencer dholki, does it also hav a CAT? How to know if even after CAT removal, exhaust is choked?
On CNG with AC on highway, its giving me 4rs/km is tht fine?