My truck has a slight miss and the pulley seems to be loose.
The most common cause of a misfire on the engine is dirty fuel injectors. It may be a good idea to have the injectors cleaned. One common issue I have seen also is a failure in the variable valve timing. Most of the time this will set a code also. Knowing if the check engine light was coming on would help. If you have a loose pulley then I would need to know which one it is. Pulleys typically do not just come loose unless the accessory that they are running has a failing bearing. I would enlist the help of a certified mechanic diagnose your misfire issue, like one from YourMechanic.
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