Old timing light saved me after 3 hours of guessing

Had a rough idle on my 04 Silverado that I chased for a whole afternoon. New plugs, wires, cleaned the MAF, still missing on cylinder 6. Finally dragged my grandpa's ancient timing light out of the bottom drawer and clamped it on each plug wire. The light was blinking irregular on that cylinder, so I swapped in a known good coil pack from the parts store shelf. Fixed it in 10 minutes. Anyone else keep old diagnostic tools around just for the stubborn cases?

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1 Comment

wood.john17d ago

That shaky light might be telling you more than a scanner ever will, if you just watch the flash pattern close enough.