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Okay, I'm gonna disagree with the 'just replace the sensor' advice on those random misfires
Had a 2016 F-150 in the bay last week with a P0300 code. Everyone online said it was always the cam position sensor on those. Swapped it, code came back in 10 miles. Turned out it was a tiny crack in the plastic intake tube between the MAF and throttle body, letting in unmetered air. The truck ran okay at idle but would stumble under load. Finding that hairline split took me almost 4 hours of smoke testing and checking every inch of the intake tract. Has anyone else found a weird vacuum leak causing random misfires that looked like a sensor?
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claire_sullivan6mo ago
My old Honda had a similar phantom misfire from a cracked vacuum line behind the engine. It's like modern systems are so sensitive they amplify tiny flaws. You see this pattern everywhere now, where a small, hidden problem gets blamed on the usual expensive part. It makes you question the quick fixes.
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phoenixwalker7mo ago
Had a Chevy with a bad PCV hose elbow once, same deal. Those plastic parts get brittle and leak just enough to throw everything off. Smoke machine is the only way to find some of them.
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