i has a problem with a ignition coil burning out, now it has a rough idle problem,i did a full tune-up--cap,rotor,wireas plugs--i changed tps switch by suggestion,i cleaned out the throttle body, i cleaned the idle air control valve,replaced egr valve----does any body have any ideas as to what is wrong or could this be a timing chain problem or a flat spot in cam--i need help!!! if i can't get any suggestions i guess i'll take it into a shop