Does anyone remember and know the name of this 80's horror movie?

I saw it as a child and remember an insane amount of plot details, everything but the name! A family gets into a car accident because the parents are making out; the parents, brother, and younger sister all make it out of the car but the older sister burns to death because her brother tied her shoelaces together. Later, the dead sister comes back to haunt her younger sister and persuades her to murder the rest of the family, one member at a time. She pushes her brother out a window, electrocutes her father by throwing an electric appliance in the bathtub, and lights her grandma's bed on fire leading everyone to think she was smoking cigarettes in bed. In the end, the mother and sister are the only two left alive and the girl goes after her mother with a pizza cutter. The mother manages to stop her and sends her away to get mental help, but in the closing twist she wakes up now alone in her house to see the ghost of her dead daughter sitting at the foot of her bed and starts screaming. Please someone help, I have been trying to find the name of this movie for 20 years!