'98 Firebird - Interior lights flicker on bumpy roads
I understand a bad or corroded door jam can cause your interior lights to act crazy or stay on, but please bare with me before coming to that assumption.
Had an issue this evening where I went to start the Firebird and upon turning the ignition key, the car started, but there was a bit of flickering in the lights on the dash. Upon putting the car in reverse, the engine shut off. I turned the key to the off position and then back to the on position, and nothing but some flickers on the dash lights. Tried again, same thing. Took the key out of the ignition, waited maybe 30 seconds, turned the ignition key and it started right up as if there was never an issue.
Then on the drive, every time I went over a bump, the interior lights would light up, and quickly fade out - They didn't immediately turn off like they do when you flick the dashboard dimmer all the way up and then down.
Any ideas on what might be going on here? If it was a door jam issue, I would expect the lights to stay on for 10-15 seconds before dimming out - But the lights, if they even become fully bright, immediately dim out which takes between 0.5 and 1.5 seconds to completely dim, based on how brightly it illuminated to begin with.
I've had prior grounding issues (for example the beloved "all 4 headlights are on, 1 is bright and the other three dim" scenario and alternator to ground,) so I'm wondering if this is an issue regarding a short in a negative wire, or a bad ground in which the next past of least resistance is across the interior lighting before reaching ground.
Please ask as many qualifying questions as necessary, I would love to get this figured out once and for all.
As a final (potentially) qualifying statement, when it's raining of directly after spraying the car off with a hose, I have issue when driving - The car's dash will intermittently flicker and when it does for the brief portion of a second, you can feel and hear the engine cease ignition. Possibly a separate issue or un-related, but thought it may be worth mentioning.