I just bought an 04 competition mach 1 last thursday. This is my first 4valve motor. Just last night the car started ticking on the pasenger side on the foward end under the valve cover. Not real loud but louder than the rest of the valve train noise. Just got a bad tank of fuel last time i filled up and put some 44k in it to help clear it up.It runs better but still has a miss every once in a while. The car has 54000 miles on it. I heard about the sparkplug could have came loose or injector noise.