As underhood specialist technicians and shop owners, you can be confident that there will be plenty of Nissans on the road for many years to come. Nissan continues to build cars and trucks that appeal to the American driver. Their customers have learned to expect many miles of solid service from these vehicles, and its our job to help them reach that goal by offering a quality, preventive maintenance plan and being prepared to handle any necessary diagnostic or mechanical repairs.

In this article, we'll take a look at some of the common problems that affect engine performance. With on-board diagnostics (OBD), many of these problems will cause a check engine lamp (CEL) and store a code. With most of us becoming comfortable and proficient while working with OBD systems, we prefer having a code; it's like having a hot tip to help pinpoint the problem. But that's not always the case.

Coil Failures
In an effort to better control catalytic converter damaging misfires, Nissan has gone to coil-on-plug (COP) ignition systems, as have most other carmakers. There have been some problems with coil failures; the easy ones are the hard failures that result in a dead miss, with the code telling you which cylinder is the offender. If that's the case, we simply confirm the failure by switching the coil with a running cylinder and confirm the miss moved with the coil. Don't make the mistake of just replacing the offending coil by ...