1997 Isuzu Hombre P0300 Random Misfire Code: Diagnosis and Solutions
I've been experiencing a persistent P0300 random misfire code on my 1997 Isuzu Hombre, which has approximately 130,000 miles. Despite replacing multiple components—including spark plug wires, plugs, two oxygen sensors, distributor cap, rotor, and upgrading the fuel injection system to an AC Delco spider— the issue remains unresolved. The truck runs smoothly for a while, then begins to stumble after driving a few miles. Shortly thereafter, the SES light activates, but the engine returns to normal operation. After some time, the SES light turns off again, only to reappear days later. I've taken it to a mechanic with over 20 years of experience in Chevrolet vehicles, who has performed most of the work and now cannot identify or resolve the issue. He has declined further inspection. While I would prefer not to sell the truck, this recurring problem has caused significant frustration after lasting about a year. Any insights into potential root causes or diagnostic steps would be greatly appreciated.
Based on the P0300 code and vehicle model, it's likely related to the 6-cylinder 4.3L engine configuration—though this is a distinct Isuzu platform, not Chevrolet. This raises questions about why a Chevy specialist is involved in troubleshooting. Could you confirm if any other diagnostic codes have appeared? What brand of spark plugs and wires were used (e.g., AC Delco)? Are there any aftermarket modifications such as remote start systems or alarms installed? Knowing these details may help identify potential contributing factors.