P0300 Random Misfire Fix: 1999 GMC Safari Van with 208K Miles

I recently diagnosed and resolved a persistent random/multiple misfire issue on my 1999 GMC Safari van, which is showing P0300 fault code. The vehicle has 208,000 miles on the odometer and previously had a MAF sensor problem—after cleaning it with an electronic wash, I still needed to replace it. Despite replacing spark plugs, wires, and the distributor cap earlier this year (due to rain-induced engine stalling), the van continued to exhibit noticeable misfires at idle, though the symptoms improved as RPMs increased. After removing the distributor cap, I observed arcing on the rotor's tab. More importantly, when I rotated the rotor in the opposite direction of engine rotation, the rotor and distributor shaft moved approximately 1/16 inch upward and could be rocked back and forth by about 1/8 inch. This behavior made me wonder if the rotor and shaft act like a top—without proper centering from the distributor bushing—and whether this mechanical play is causing misfires that trigger the P0300 code. This observation suggests that worn or missing distributor bushing may be contributing to inconsistent spark delivery, leading to random misfiring. I believe replacing the distributor bushing could resolve both the idle misfire and the P0300 code in this high-mileage 1999 GMC Safari van.