I have a 97 murqury couger. I changed the pluges, wire, but it still will not run. It tries to start but it wont catch on. It has a week spark coming from the coils. Please help me!

If the engine cranks at a normal speed,and the starter seems not to be dragging ,there should be a hot enough spark to start,and run.
Check for a voltage drop in the starting system.Make a visual inspection of the battery cables, and all the starter connections, tight,loose broken,corroded,clean as needed. ect. Check for a bad connection or corroded wiring near the battery,a wire that comes off the positive battery cable may not be feeding the ignition the voltage needed,since the starter takes a good bit even if it is in good condition.Look for a starter relay between the battery and the starter,check cable connects.Check engine grounding cable too. You could have bad coils or a bad ign.module or a bad crank sensor. You may ask a jobber to test the module first.Before you buy any coil pack,or crank sensor. I hope this helps you some.The crank sensor is not expensive,just the labor will be.