Two problems related to power train have been reported for the 2003 Nissan Frontier. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Nissan Frontier based on all problems reported for the 2003 Frontier.
Wheel bearings keep backing off spoke with other people who own a Frontier and they have same problem this is a saftey issue have to tighten them regularly.
Nissan murano 2003 has problem with pressure sensor inside transmission. This causes the vehicle to hesitate, 10-15 seconds before you can accelerate. This only started 2 weeks ago and I have 89k miles on it. I almost was stuck by an oncoming vehicle due to the hesitation. There are many more stories like mine on edmunds. Com. Nissan does not acknowledge any problem with the transmission but clearly states that the defect was corrected in the later models. Big safety issue, please look into this ASAP before someone is killed.