2021 Nissan Frontier: While in gear at idle, rattle near passenger foot well
Common wear/failure (not a recall)
Symptoms
Owners of the 2021 Frontier report: while in gear at idle, rattle near passenger foot well. CarComplaints.com lists 1 owner complaints, average mileage 18,000 miles.
NHTSA has 2 owner complaints for the 2021 Frontier in this area. Examples:
- NHTSA complaint ODI #11770806 (filed 10/13/2026): “While driving on a two lane state route road towing a rv at approximately 60 mph, the first indication of an issue was an amber abs warning light accompanied by an amber traction control light. shortly after a red brake warning light illuminated. shortly aft…”
- NHTSA complaint ODI #11511824 (filed 03/14/2023): “Numerous complaints of problems with bad/defective engine mounts .…”
Likely causes
Sources do not establish a single root cause; diagnosis is needed. Owner-reported fixes are listed below.
Fix, in plain English
Most common owner-reported solutions on CarComplaints.com: heater core bracket (1 reports). Check for open recalls and extended warranty coverage with a dealer before paying out of pocket.
DIY difficulty: Pro
Internal engine work (lifters, oil consumption, fuel dilution diagnosis) requires engine teardown or dealer software/tests. (Our assessment.)
Cost
No sourced cost range: get a written quote after diagnosis.
Typical parts (search links, no affiliate codes)
AutoZone · O'Reilly · Advance · RockAuto
Sources
- CarComplaints.com: While in gear at idle, rattle near passenger foot well (2021 Frontier)
- NHTSA complaints API, 2021 Frontier
Page last updated .