1996 Nissan Quest Owner's Manual - Page 223

Incorrect ignition timing may result in spark knock, after-run, and/or overheating, which may cause excessive fuel consumption or engine damage. If any of the above symptoms are encountered, have your vehicle checked at an authorized NISSAN dealer or other competent service facility. However, now and then you may notice light spark knock for a short time while accelerating or driving up hills. This is no cause for concern, because you get the greatest fuel benefit when there is light spark knock for a short time under heavy engine load. ATI0507 ENGINE OIL AND OIL FILTER RECOMMENDATION Selecting the correct oil It is essential to chose engine oil with the correct quality and viscosity to ensure satisfactory engine life and performance. NISSAN recommends the use of a low friction oil (energy conserving oil) in order to improve fuel economy and conserve energy. Oils which do not have the specified quality label should not be used as they could cause engine damage. 9-4 Only those engine oils with the American Petroleum Institute (API) CERTIFICATION MARK on the front of the container should be used. This type of oil supersedes the existing API SG or SH and Energy Conserving II categories. If you cannot find engine oil with the CERTIFICATION MARK, an API SG or SH, an Energy Conserving II oil with the API Service Symbol may be used. An oil with a single designation SG or SH, or in combination with other categories (for example, SG/CC or SG/CD) may also be used if one with the