the car has 99564 miles so l changed the sprak plugs and now it knocking lput the old plugs back in it and it stills knocks

Take it to a mechanic because rod knock means the engine is about to go.

you might have a bad cylinder, it could be getting too much fuel, or you could have a rod broken, knocking can be bad, and the check engine light is telling you something is wrong. l would take it to a dealer or repair shop for further help. It could be a band injector causing the cylinder not to get enough gas to fire, or it could be a bad coil not firing at all, that could cause a knock.

one you might have crossed a plug wire or your timming is off and it could be the cat needs changing on the exzaust.

l dont think changing your spark plugs has anythgint o do with it knocking, if its knocking as you say it is, it probably needs oil, check all your fluids . . . oil, tranny fluid, power steering . . .the absolute easiest way to tell whats wrogn with it is take it to a shop and have them run a diagnostic . .plaus if you let them do the work on it, they wont charge you for the test, otherwise, itll probably be about 50 bucks . . .

With many manufacturers they program the check engine light to come on at milestone intervals. For instance 100,000 miles would be a typical time for the manufacturer to have this light come on. The thing is, u have to take the car to a factory certified mechanic to get the check engine light switch reset to make it go off until the next milestone marker. It is not necessarily an indicator that there is anything wrong with ur engine, it more likely it is an indicator that the manufacturer would very much like u pay a factory certified mechanic right about now.

l believe the pinging is unrelated, & u should treat the individual symptom. It sounds like u may have jumped time. Perhaps u reversed a sparkplug wire when u changed the plugs the first time. Check ur firing order. Have u purchased fuel from a new or known low quality distributor lately? Is ur engine cooling system completely healthy? Is it possibly heat related.

Those r my 2 cents anyway.

Good luck.

Something may have fell on top of a piston when the plugs were removed. You may remove one at a time, crank the engine and it might come out if not stuck in the piston.

Unless the electrode became dislodged or the porcelain at the base of the plug broke or cracked and is causing a detonation you have another problem.
You have a COP (Coil On Plug) ignition system and you could have a week coil.
Post your question on this website and you can get some of the best information on the Interweb.

http://lincolnsonline.com

Check the Tech section too and you will be supprised what is listed.

If it did not knock before, something fell down in the spark plug hole, like a gravel.

Sounds like you dropped something down the spark plug hole. Sorry to say it.

Take it to a mechanic! It could just be a simple problem. l purchased a 2000 Lincoln LS in April and the check engine light has came on 3 times for 3 different reasons and the car only have 70000 miles on it, mostly for minor problems like someone put the spark plugs in incorrectly.

l have two town cars with high milage,and never a problem. My truck check engine light comes on,but it is just a bad sensor. It has 165,000 on it,and still runs great. It is an F-150 Ford. In some Ford cars the check engine light may come on,and all you need to do is tighten the fuel cap. Crazy but true.