Owners of 2001-09 B4000 pickup trucks may complain of an irritating buzzing sound from the engine compartment. According to Mazda, the noise typically occurs at about 1900 rpm under light throttle conditions and is most likely due to loose ignition coil bracket retaining bolts. Tightening the bolts to a new, revised spec should eliminate the annoyance immediately.
The illustration above shows the location of the two coil bracket bolts. Once there, loosen the bolts, then use a torque wrench to tighten both to 89 inch-lbs. Now turn both bolts an additional 45 degrees and the fix is complete.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].