My car keeps over heating and shaking plus my engine light keep flashing
Sounds like you have a clogged catalytic converter or muffler.
Check the cooling system as well. You may be low on coolant because of a leak. When these cars overheat they will sometimes go into "limp home mode". What happens is the computer starts alternately firing different sets of cylinders to keep you going and the cylinders that aren't firing act like an air pump to help carry away the excess heat to avoid engine damage. I had a situation with my '00 Grand Prix back in December. One of the plastic coolant elbows came apart and spewed hot coolant all over the engine compartment. The coil pack directly above the elbow got the brunt of the hot coolant and fried it. I too was still getting a misfire on cylinder 3. I replaced the coil pack and it was fine. HTH. -Jim
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