Mercury Marquis Repair Question
Jumped time?

Answer
No what I see in the pic is normal chain deflection...if therer are no codes when you say the engine runs poorly, how so? Any backfires, does it stall..etc..etc.
When was the last tune up? try dissconnecting the neg battery cabel for about 20 sec. This will clear the memory, and the computer will re-learn by your driving habits...where you have the engine in this state, and zooming in on it, why don't you reset the marks any way!
There are no trouble lights lit up except for the occasional air bag light which was covered earlier here. no check engine light. no backfires. It is hard to start and once it is started, it has to be coaxed to run by revving the engine for a few seconds and then it will finally go to a rough idle. The battery has been disconnected enough times by the the car just sitting and it needing to be recharged. I did drive the car 40 miles from where it was given to me from. I will go ahead and replace the chain and gears and reassemble - the timing marks dont have to be "dead on"?

Yes! Take the chain off and rotate the crank to match the cam.