I own a 1987 AE82 SOHC 1.6L corolla 4AC (auto) engine. If I press down (Not fully but alot) on the accelerator the car sort of stalls ie it fumbles and dosen't speed up untill I ease off the accelerator. Also say I'm travelling at normal speed and which to speed up a little bit, when I press the accelerator pedel more nothing happens, but when I press it down even more the car drops down a gear (to second) and speeds up. All I wanted to do was go just a little faster not make the engine rev up to 3700rpm. What could be wrong with it?