97 grand am spark plugs

not really sure if this is the best place to post this question, but here goes. i just changed all 4 spark plugs in a 97 grand am, and now the engine rocks while running, and the check engine light has come on, anyone have any ideas on why changing spark plugs would cause this?

Did you check  that no wires or vaccum lines have come loose? Also are the plugs gapped correctly. When you changed plug wires did you do them 1 at a time or pulled all off at once? If you pulled all at once it is pssible you have crossed 1. Go back through and check all connections & firing order.

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Make sure when you lower the top section with the coil packs down onto the plugs the wires have snapped onto the plugs correctly. The wires are so short and hard to see while you are lowering it back into place that you may have missed one of them. 

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'85 Toy

Fireing order is messed up. (wrong wire to the wrong plug)

If his '97 is like my '96 Grand Am it's impossible to cross the wires. One of them might not have snapped down on the plug tip, but they are so short they can't go anywhere except the right plug.

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'85 Toy