1993 GMC Suburban Owner's Manual - Page 271

If you're using fuel rated at 87 octaneorhigherandyoustillhearheavy if youhearalittle knocking,yourengineneedsservice.Butdon'tworry pinging noise whenyou'reacceleratingordrivingupahill.That'snormaland youdon'thave to buya higher octane fuel to get rid of pinging. It's the heavy,constantknock that meansyouhaveaproblem. Whataboutgasolinewithblendingmaterialsthatcontainoxygen,suchas MTBE or alcohol? MTBE is "methyltertiary-butylether."Fuelthat fine for your vehicle. is nomorethan 15% MTBE is Ethanol is ethylorgrainalcohol.Properly-blended 1Q% ethanol is fine for your vehicle. fuel that is no morethan Methanol ismethyl or woodalcohol. Gaso/ines for Cleaner Air Your use of gasolinewithdetergentadditiveswillhelppreventdepositsfrom forming in yourengine and fuel system.Thathelpskeepyourengine in tune It's goodforyourvehicle, and youremissioncontrolsystemworkingproperly. and you'llbe doing yourpartforcleanerair. Manygasolines are nowblendedwithmaterialsthatcalledoxygenates. GeneralMotorsrecommendsthatyouusegasolineswiththeseblending materials, such as MTBE andethanol. By doing so, youcanhelpcleanthe air,especially in those parts of thecountrythathavehighercarbonmonoxide levels. In addition,somegasolinesuppliersarenowproducingreformulated gasolines. These gasolines are speciallydesigned to reducevehicle emissions.GeneralMotorsrecommendsthatyouusereformulatedgasoline. By doing so, youcan help cleanthe air, especially in thoseparts of the countrythathave high ozonelevels. if theirgasolinescontain You shouldaskyourservicestationoperators detergents and oxygenates, and if theyhavebeenreformulatedtoreduce vehicleemissions. 6-5