I had a 99 Mercury that done the same thing with the cyclender compression. It ended up being my lifter was bad and not letting the valve close. My oil light would also come on when I was ideling. After getting them fixed and 500.00 later my car engine died from the oil pump going bad. I am not saying this is your problem but it just sounded a lot like mine. Although my engine would tick when the lifter was going bad. But if it is make sure you also have the oil pump looked at. I was told that was probably what my problem was the whole time because the oil pump was not getting enough pressure up to the lifter, then the pump decided to die completely.
Ford Co. Vehicals owned:
1989 Ford Tempo AWD - Sold
1993 Mercury Sable LS - Ran it till it died
1999 Mercury Sable LS - Sold
2006 Ford Fusion SE - Sold
2013 Ford Taurus Limited 302A AWD