Some Mazda 2001-2009 B4000 vehicles may exhibit a buzz noise from the upper engine area at about 1,900 rpm under light load acceleration.

Check fasteners (“A” in illustration) that attach the ignition coil bracket to the intake manifold for proper torque. These two bolts should be torqued to a value of 89 in.-lbs. (10 Nm), followed by an additional 45 degrees of rotation.