I had a 303, checked all plugs and coils. looking like the cylinder is bad. I noticed my mechanic put 7 quarts of oil in and its only a 4.6. could the excess oil cause misfire, rough idle etc. Now everyone seems to think its a cylinder or vlave issue? it also seems a little suspect that a) the rough idle and power loss happened less than day after i got it back form the mechanic and b) my mechanic told me after i brought it back in he thinks its a carbon build up or dirty injector and to drive it another couple hundered miles and see if it clears up.
My neighborhood buddies (both competent mechanics) did some elimination work and say its a cylinder issue. gonna check compression soon. I 'm feeling something is fishy aobut my mechanics work....help... i am a carpenter not an engine guy.
sorry if I changed the thread too much.