2002 pontiac grand prix se spedometer and exceloration prob

My car ran pretty well with some problems here and there but about a week ago i got it my car it started fine backed it out and drove it down the street i looked at my spedometer and it was goin crazy first to 40 then 20 then 0 back to 40 when i tried to give it some gas the rpms went really high and the car jumped into next gear. At first it seemed like a tranny problem but after i drove it for a bit that day the problem went away and was gone for about 4 days when i woke up again it started the same thing. Im thinking my fuel filter mig[/quote]ht has a clog in it but im not sure??? Thanka