I have a 92 sc400 and Im having a hesitation problem at half throttle. I cant feel it so much at 1/4 throttle or full throttle. But at half throttle it chugs pretty bad. Ive changed the plugs and wires NGK for both, and the cap and rotors. Ive tried injector cleaner,still the same. It used to do it a little bit but it just keeps getting worse. Im thinking maybe coils or AFM but I dont know. Any ides would be great.