Hi there I just bought a crown Victoria and the problem is the car is shaking when I drive ,I'm not sure if it's the spark plugs

You'll first need to find out if you are lacking fuel or spark to know where to go next. Do a basic test for fuel pressure with a gauge and spark at the plugs when it fails to start.

Recheck the spark plug wires to make sure that they all seated properly. Also, make sure that you got the wires on the correct plugs.

In the sides of the head

The spark plugs are on top of the enging under the plug wire boots,which are sometimes coloured orange

the spark plug socket size is 5/8"x 3/8" drive and you need a 3/8 drive 3" or 6" extension with a 3/8 drive ratchet and a spark plug gapping tool to make sure the plugs are gapped properly.the drain plug is either a 1/2" or 7/8" wrench depending if it has been replaced due to being bad.

Attempt to change all of the spark plug wiring and spark plugs. Then start the vehicle.

Well first off you need to put Motorcraft spark plugs in your vehicle, and it sounds like you have a bad coil..Take it to autozone, or Advanced Discount..depending on your location, an they can scan it for free. An then you will know what direction to go in.. Goodluck..

I would try to replace your spark plugs, and spark plug wires, My 88 Vic did the same thing...now it runs like a champ....you could also try fuel injector cleaner.

Pull out the spark plugs one at a time and check to see if they are firing. I had the same problem while merrily driving at 70mph. All of a sudden I lost spark in one spark plug wire. It just went without warning.

if you turn the key and the engine spins but doesnt fire try checking the timing for it to make spark at the time you need it to ,if it's out it wont catch and run or check for spark at the spark plug make sure it has spark use a dummy sparkplug in the boot and hold it on a ground and crank engine look for a blueish spark and if you have bare hands holding it you'll get a good jolt (insulated pliers)