top off your transmission fluid. make sure there are no leaks or cracks under the transmission's belly. the shift solenoid (on the 4cyl) is over the warm & cool lines that go from and to the transmission. it's like a $75 part. try a junk yard or online. cheap fix. also the electrical code could also mean your battery terminals probably have corrosion & need to be cleaned. clean the battery terminals and electrical connections to the battery with a wire brush. put the battery grease on and green & red protectors on. if that doesn't work, your battery or grounding points may need to be cleaned or worse case scenario maybe the battery is bad? maybe I'm wrong. hope this helps.
