If a cold air intake was installed in place of the original intake system, the misfires may be caused from a contaminated/damaged Mass Air Flow sensor. You can try cleaning the MAF sensor with an aerosol MAF sensor cleaner to see if that helps. If not, then have a scanner connected that can do real time monitoring. Drive the vehicle and monitor the MAF sensor readings relative to throttle position. If you see something like 80% mass air flow at 100% throttle opening, the MAF sensor is defective and causing the misfires.
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