You may want to remove the coils and the Ignition Control Module that they are mounted on. It's just a flat plate. Clean the bottom and top of any corrosion that has built up under there and check - clean the ground connection which is also right there attached to the module.
Apply a
light film of Dielectric Grease to the bottom surface of the ICM and reassemble.
Even if this is not part of your problem it is good preventive maintenance.
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98 Riv, 102K Miles, EBC, LS1 Ft.Calipers, STB, Addco Rr Sway Bar, 180* stat., SSAC Headers, HF Cat, 1.9's,
105# springs, MPS 3.4, DHP tuned by the Deekster.