I have a 1995 sc 400 with 210k miles, the timing belt 10k miles new. The problem I having is.

My engine was missing when idling, I changed the plugs and wires. I thought this had solved my problem, but a few days later it starting missing again. When the vehicle is stopped it act like it wants to cut off and it will cut off if I do not give it gas. Sometime when I’m driving I can feel a hesitation in the engine. Any suggestions on what might be the problem…