I have a 94 4runner which is bogging under 300 rpm after that it takes off. ive changed the plugs cap and rotor and nothing changed. I took the filter out of the EGR mod and its real dirty and goneright hard. after a few attempts to clean it and still nothing i made a run up the road with out the filter in the EGR and it ran perfect. my question is can i leave the filter out whitout causing damage or should i replace it with something?