Spirit 1992

I have a Spirit 1992 Automaticoque has given me a lot of headache lately since when you turn on them and put the drive the revolutions are lowered to "0" and turns off, or sometimes underway it starts to pull and I have to keep the accelerator to the bottom so that it does not go out and suddenly runals and pulls well again. Please someone pity from me and give me your opinion. I await news soon. THANK YOU