On teh 2.5 L duratech the ticking noise could be coming from teh plug boots, This was the case on my engine i pulled out the plug wires and teh boto on one of tehm was fried. it ahd a white kinda burned sopt on the side, the ticking was actailly the arc of electricity jumping to the engine block, and this in tunr did not give the spark plug any spark and casued the engine to idle really rough. I'd check that out this engine only had 80,000 miles on it. hope this helps ya out
