This used to be used simply to prevent fuel from spilling out. No. The fuel cap is an emission control component. The fuel cap maintains adequate fuel pressure by closing the gas tank. In addition to the CEL (Check Engine Light), a loose or broken fuel cap may cause low mileage. If damaged, replace the fuel cap every 50,000 miles.

An oxygen sensor measures the quantity of oxygen in an exhaust system. A dirty, damaged, or malfunctioning O2 sensor (or sensors) reduces engine performance and fuel efficiency. Pre-1996 O2 sensors should be replaced every 50,000 miles. ODBII (On-Board Diagnostics, 2nd Generation) has a 100,000 mile service life.

The O2 sensor is in the exhaust system. The owner's handbook (or service manual, which is different) might assist you locate the sensor and identify the replacement sensor you need. Ensure you have the right sensor for your engine.

Spray penetrating oil on the sensor base once the engine has cooled. Disconnect the wire. Remove the old sensor using a 7/8-inch wrench or an O2 socket and ratchet. Lefty loose, righty tight. Clean the exhaust threads with a brass brush or an old toothbrush. Install the replacement sensor and apply anti-seize compound to the threads.

The EVAP system prevents gasoline vapors from leaking into the environment. Moisture in an EVAP canister prevents the filter from collecting gasoline vapors, creating excessive fuel pressure. This may produce a CEL, power loss, and poor fuel efficiency. According to the manufacturer, the EVAP canister/filter should be changed every 50,000 to 75,000 miles. If the canister gets saturated, you may need to replace the complete component.

Disconnect the battery after you've found it. Disconnect the wire connection and lubricate the bolts. Before detaching hoses from the canister, label them with tape. Remove the canister and the mounting hardware. Remove the holding clamps and replace the filter if it is removable. Reinstall the canister in reverse order.

Nothing is worse than a flat tire. But it gets worse when the spare tire holder under your truck or SUV won’t budge due to corrosion caused by mud and road salt. First, read your owner’s manual to figure out how your spare-tire hoist system operates and to be sure you have all of the factory-supplied tools you need to lower the spare.

To service the hoist, you’ll need a floor jack and jack stands to safely work under your vehicle. Spray the cable and hoist assembly with penetrating oil. Give it some time to soak into the assembly, then tap on the wheel with a hammer to help vibrate the penetrating oil into the assembly. Lower the vehicle onto the ground and try to lower the spare. If the assembly and cable are badly rusted or seized, they’ll need to be replaced by a pro.

The EGR (Exhaust Gas Recirculation) valve is another critical emission-control device. The EGR helps lower NOX (nitrogen oxides) tailpipe emissions by lowering combustion temperatures. This helps engines run cleaner and last longer. Although an EGR valve should last the life of your vehicle, a good cleaning every 50,000 miles is recommended. A dirty EGR valve, clogged with carbon, can cause rough idling, stalling, hesitation on acceleration, a failed smog/emission test and of course the dreaded CEL coming on. Use your owner’s or service manual to locate the EGR valve.

Purchase an EGR valve gasket(s) before starting. Disconnect the battery, disconnect the wire connector and spray the mounting bolts with penetrating oil. Use masking tape to mark hoses attached to the EGR before disconnecting them, then remove the mounting bolts and valve. Thoroughly clean all gasket mounting surfaces. Use a soft-bristle brush to remove excess carbon build-up. Spray or soak the EGR valve in carburetor cleaner or cleaner solvent specially designed to clean EGR valves. Scrub the EGR again and flush with clean solvent. Check the pintel valve — usually located on the underside of the valve, in the center— it should easily move up and down after cleaning. Install a new gasket and reverse these steps to reinstall the valve.

Performing regularly schedule maintenance and making timely repairs will save you money, ensure your driving pleasure and safety and help prevent other future costly repairs.

Thank you to our friends at family handyman for providing the original articles below:

Source: https://www.familyhandyman.com/article/diy-car-repair-maintenance-tasks/