Having problems with your 1990 Mercury Grand Marquis ?
How to change spark plugs? - 1990 Mercury Grand Marquis
On top of the engine lies coil packs, maybe 4 of them on your vehicle--you need to unplug them and pull them out of the socket. You will then need a tool that is long enough, about 10 inches long, to unscrew the spark plugs which are located in the holes from which you removed the coil packs.
Repair Help & Product Troubleshooting for 1990 Mercury Grand Marquis
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