1998 Buick Park Avenue Owner's Manual - Page 277

f The 8th digit s your vehicleidentification number (Vm) shows the code lettee for your engine. You will find the VIN at the top left of your instmment panel. (See "Vehicle Identifkation Number'' in the Endex.) Things you might addto the outsideof your vehicle can affect the airdaow around it. This may cause wind noise and affect windshield washer performance. Check with your dealer before adding equipment the outsideof to your vehicle. If you have the 3800 engine (VIN Code use regula unleaded gasoline ratedat 87 octane orhigher. If you're using fuel ratedat the recommended octane or higher and you hear heavy knocking, your engine needs service. But don'tw r y if YOU hear a littlepinging or noise when you're accelerating or driving up a hill. That's normal, and YOU don't have to buy a higher octane fuelto get rid of pinging. It's the heavy, constant knock that means you have a problem. If you have the3800 Supercharged engine(VHN Code I), use premium unleaded gasoline rated at 91 octane orhigher. With the 3800 Supercharged engine, in an emergency, you may be able to use a lower QC~XE -- as lowas 87 -- if heavy knocking does not occur. If you are using 91 cxhigher octane unleaded gasoline and YOU hear heavy knocking, your engine needs service. 6-3