I can definitely check the coil. My manual says it needs to be clean and dry to work correctly, and it's quite possible it's got some grime or is going bad.

Thanks for the tips!

'87 Raider - 2.6L Rebuilt by me, BSE installed.
Superwinch manual hubs. LSD, Squirters and bouncy seat added. Cobra CB w/ PA (PA coming soon). 31x10.5x15 Futura Dakota rubbers; Pro Comp Add-A-Leaf w/ Rancho RS500's in the rear, KYB's up front.