car engine acceleration problems

Chevy Caprice

Acceleration problems

Hi my name is Jason. I have a 1995 Chevy Caprice classic and I’m having engine problems when i hit the accelerator my  car goes 5,6,7 mph and at random moments has a boost of power and goes normal speed 80 – 100 mph  what would be the problem i changed the gas filter the spark plugs and nothing… if needed more info just ask