Modern cars share the same sensors to operate fuel, ignition, transmission, traction control, brakes and cruise control. It is likely one sensor or circuit has failed causing multiply systems not to operate properly but a scan tool is required to retrieve trouble codes stored in the computer of your car.
I have a 2002 Oldsmobile Alero, 2.2, 4 cylinder engine. I had to replace my transmission twice before I narrowed down the cause of my transmission hard shifting and high rpms. I had a faulty IAT (intake air temperature) sensor, and TPS (throttle position sensor). I also replaced the connections for both sensors. The sensors cost around $110 for both of them and it cured the hard shifting in my transmission. HTH.