I have a feeling it is the rear three plugs. However, if you want to check the coil, it is somewhat involved. I will give you the steps as needed and the continue once I hear the results from you.
To begin, we need to make sure the proper voltage is getting to the coil.
First, remove the connector at the coil.
See the attached pic
As you can see, there are 4 pins. One is the B+ and the others are for individual cylinders. First make sure there and no damaged pins in the connector or corrosion. If that checks good, using an ohm meter, check for primary resistance between the B+ terminal and each of the others (one at a time). If primary resistance is more than 2 ohms, the coil is bad.
Get that far and let me know what you find.
Image (Click to make bigger)
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Wednesday, September 2nd, 2015 AT 7:11 PM