Mercury mountineer running fine then started running rough

Hopefully, replacing the camshaft position sensor will fix it?

Flashing light means blocked exhaust

I think your being had over here ,if i had my head under the bonnet i could tell you but from afar ,3000bucks sounds a lot for a 99 motor thats worth 500 to 1000 pounds tops even if it is a honda ,i can buy a monster jag here under a 1000 pounds and at 10 dollars us a gallon you know why?

Sables always have radiator problems also ive owned 2 and first thing ive done when bought them is replaced the radiator and added an external cooling system

Hi
Your symptom shows sign towards Starter motor is sticking or tooth in the flywheel is broken.

the problem you are discribing would lead me to belive your fuel filter is clogged which is a simple fix 3 dollar part at any part store or on the worse hand your fuel pump itself could be weak you can open the gas tank cover and have another person turn the truck key to the on position without going far enough to start you will hear a faint whining noise if it is going bad or a louder noise if it is fine Good Luck

Computers aren't ALWAYS correct. If a code wasn't cleared after the original problem, it will read the same codes off to the diagnostic. I would remove the wire connector to each injector while it's running. If one of them makes no difference THAT is your culprit. Let me know please!

You need to check the fuel pressure, if not enough it will run rough.

The CAMshaft position sensor is faulty.