Replace Your HEMI Engine's Spark Plugs The tasks listed so far are widely considered routine maintenance that should occur every 1,000 to 3,000 miles or as indicated in your owner's manual.

The fix is the replacement, not just the re-gapping as originally thought, of all 16 spark plugs (two per cylinder) of the 6.2-liter HEMI engine, the only one in the Dodge Challenger lineup ...