1995 GMC Sonoma Owner's Manual - Page 231

To remove the rectangular air cleaner filter the 4.3L (VIN W) engine, for open both clamps and push the rear of the air cleanerback toward the rear of the engine compartmentto change the filter. While reassembling the air cleanerassembly, ensure that the air cleaner cover tabs are fully inserted into the slots in the air cleaner housing. On the 4.3L (VIN W) engine, also make certain that the PCV air tube is properly seated in the left hand valve cover. Refer to the Maintenance Schedule to determine when to replace the air filter. See "Scheduled Maintenance Services" the Index. in A CAUTION: Operating theengine withthe air cleaner off can cause you or others to be burned. The air cleaner not only cleansthe air, it stops flame if the engine backfires. If it isn't there, and the engine backfires,you could beburned. Don't drive with it off, and be careful working on the engine withthe air cleaner off. NOTICE: If the air cleaner is off, a backfire can causea damaging engine fire. And,dirt can easily getinto your engine, which willdamage it. Always have air cleaner in place when you're driving. the 6- 13