According to carcomplaints.com, problems with the engine, specifically a blown head gasket, are the most commonly reported problems with the 2005 Nissan Sentra. Among verified problems that owners reported to Repair Pal, the most common, reported by 148 Sentra owners, was failure of the crankshaft and/or camshaft sensor. Repair Pal also received 50 verified reports of failure of the electronic throttle actuator, which causes a loss of power, and 50 verified reports of problems with the fuel pressure regulator.
Failure of the fuel pressure regulator allows fuel pressure to bleed off, making the car hard to start, and requires replacement of the regulator.
Identified problems with the 2005 Nissan Sentra that resulted in dealer recalls include an incorrectly manufactured vapor hose in the fuel tank which caused fuel leakage, overheating of the crankshaft position sensor causing the engine to stop without warning, and excessive internal pressure in the passenger side airbag, creating the possibility of an airbag rupture.
The National Highway Traffic Safety Administration received 135 reports of problems with the 2005 Nissan Sentra. The majority of reported problems involved the engine and engine cooling. Four reports had to do with vehicle speed control. The NHTSA also conducted two investigations regarding the 2005 Nissan Sentra; both related to problems with the air bag inflators leading to airbag rupture.