The base model Ford Mustang comes equipped with a sequential port fuel-injected 3.8 liter V6. The Bosch style fuel injectors in this system are very durable, but from time to time one will break down due to clogging or electrical failure. Replacing the injectors is well within the abilities of the average do-it-yourself mechanic.
Remove the air filter housing and the flexible hose attaching it to the throttle body. Then remove the upper intake by disconnecting the throttle cables and any coolant or vacuum lines. This will give you access to all the upper manifold bolts. Pull out the upper manifold bolts and upper manifold, and set them out of the way.
Disconnect the fuel lines and electrical connectors. Do this by first inserting the fuel line disconnect tools into the ends of the connectors to release the connectors; twist while pulling to slip the end of the fuel lines from the injector rail. Then unplug the injector electrical connectors by removing the retaining clips and pulling the connector from the injectors.
Unbolt the injector fuel rails from the lower manifold, and pry up on the rail to release the rail and injectors. Once the bolts on the rail are removed, the only thing holding the injectors in the manifold are rubber O-ring seals that may have become stuck over time. Make sure to remove the old seals if they stick to the manifold, as the new injectors are supplied with new seals.
Remove the injectors from the rail by removing the retaining clips and twisting while pulling until they pop loose. Be sure to keep the retainers as new ones are not usually supplied with the injectors.
Install the new injectors in the fuel rail by applying a small amount of silicon-based grease, and twisting while pushing in. Then reinstall the retaining clips, and rotate the electrical connector into their proper orientation on the rail.
To put the fuel injectors into the manifold, apply a small amount of silicon grease to the rubber O-ring seals and position the injectors into their openings in the manifold. Then press down to push the injectors into place inside the openings, and reinstall the fuel rail bolts. Next, plug the fuel lines in until you feel them snap into place, and then plug in all the injector electrical connectors.
Remove the old upper to lower manifold gasket, and position a new one on the lower manifold. Then sit the upper manifold carefully into place and start all the bolts. Tighten in a pattern beginning in the middle and working outward to the ends of the manifold.
Reinstall any vacuum lines and coolant hoses, and top off the coolant. Then return the air filter housing and flexible hose.
Prime the injectors by turning the ignition key off and then on again three or four times; then start the engine. Check for any fuel or coolant leaks, and test drive the vehicle if no problems are found.
