this week as i drove my ford died when i accelerated from a stop light. I re fired the engine and found that i could feather the accelerator peddle and finally come up to speed, but had to continue to feather the peddle lightly to maintain 45 mph. i have changed the air filter and what appears to be the in frame fuel filter. Now if i attempt to reveve the engine the rpm ossolates from 1000 to 2500 up and down with the peddle on the floor. Any fixes?