Well on my 95 plymouth neon, I get going and its slugish and dopesnt actually want to move. It makes a hissing like sound while trying to accelerate and when it does accelerate when i hit around 55 mph it just shakes and doesnt want to go any faster. If you know anything about what could be wrong please help me out its my ownly car and I need it to transport my 3 year old son places.