What cause your 1995 Chevy truck to run rough and have black smoke out exhaust?

A rough-running 1995 Chevy truck that emits black smoke from the exhaust is typically indicative of an overly rich fuel mixture, meaning too much fuel is being delivered to the engine. Common causes include a malfunctioning fuel injector, a clogged air filter, or issues with the engine's sensors, such as a faulty oxygen sensor or mass air flow sensor. Additionally, problems with the ignition system, like worn spark plugs, can also contribute to poor combustion, resulting in rough operation and black smoke. It's advisable to have the truck diagnosed to pinpoint the exact issue.