Ford’s 4.6L V8 engine was used on several models, including E-Series, Expedition, Explorer, F-150, and Mustang, from 1990 to 2014. The 4.6L engine is one of the most reliable engines ever made by Ford.
Ford’s 4.6L engine improved over the 5.0L 302 pushrod engine that it replaced. The 4.6L can last well over 100,000 miles when properly maintained.
Ford’s 4.6 engine is straightforward to work on due to having a very open and well-designed top. For example, it is effortless to access and replace the spark plugs, coils, and wiring harness. Replacing injectors is very simple as well.
1. Engine Missfire
Check engine lights on with misfire codes p0300 – p0308 are most common due to spark plug
or ignition coil failures. If you have the P0300 random misfire or undetected misfire, Ford has released a powertrain control module update to fix this problem.
2. Injector Problems
There were a few instances of injectors clogging or sticking open, causing P0172 or P0175. When reading the fault codes via the OBD-II port, you’ll notice that fault codes point to faulty oxygen sensors. Often injector problems are miss diagnosed as oxygen sensor problems. The oxygen sensors report to the PCM what they are detecting. These codes are the management system saying that the exhaust is rich or past its limit. A common symptom is a black smoke at engine start-up. That is a sure sign of a leaking injector.
If this problem is ignored for a long time, catalytic converter failure is due to overheating and melting. Eventually, the driver may notice excessive causes of backpressure, check engine light flashing, and poor performance.
3. Fuel Pressure Regulator
Fuel pressure regulators on the fuel rail could leak their supply vacuum port with raw fuel. If you suspect a fuel injector or a leaky regulator, use a fuel pressure test gauge to perform a leak-down test or a YOUCANIC diagnostic scanner that can do an injector test.
This is a fire hazard. Take precautions or have a professional do this for you. Check the exhaust system for excessive back pressure if you have one that melts, or the sensor is melted. It’s a good possibility there was a misfire or a leaking injector in the past, even if a misfire isn’t present.
4. Exhaust Gas Recirculation Problems
The exhaust gas recirculation system may fail, and set codes:
- P1408: EGR Out Of Self-Test Range
- P0401: Exhaust Gas Recirculation (EGR) Flow Insufficient Detected
Generally, p1408 or p0401 are exhaust gas recirculation system codes.
The P0401 was usually a faulty DPFE sensor (EGR pressure differential sensor). The DPFE sensor could get moisture from condensation in the exhaust system and fail, or the hose from the exhaust bleed fitting could fall off or melt.
5. Oil leaks
Overall the 4.6L Ford engine does not suffer from significant oil leaks. They were occasional valve cover gasket or front crankshaft seal leaks.
Ford 4.6L engine was used in police interceptor as well, in which case the oil coolers often leak externally or into the cooling system. Replacement of the cooler and chemical flushing of the cooling system took care of that.
6. Front cover noises
Timing chains, guides, and tensioners would fail if maintenance were not done at proper intervals. Oil changes with filter and just plain common sense would keep this engine going for a long time. It is strongly recommended to use quality fuel to keep it running smoothly. Keep in mind that it is not necessary to use higher octane fuel.
Any vehicle equipped with a Ford 4.6L engine can last a long time. Many are installed in police interceptors cars, which often last a very long time. The odometer in the 250,000-300,000 range is not unheard of in a Lincoln Town Car or F-150. Overall, Ford’s 4.6L engines are dependable.
- Ford Crown Victoria
- Ford E-Series
- Ford Expedition
- Ford Explorer
- Ford Explorer Sport Trac
- Ford F-150
- Ford Thunderbird
- Lincoln Aviator
- Lincoln Continental
- Lincoln Mark VIII
- Mercury Cougar
- Mercury Grand Marquis
- Mercury Marauder
|Configuration & cylinders||V configuration, eight cylinders|
|Vehicle engine orientation||Longitudinal|
|Valve configuration||Single overhead cam (SOHC) / Dual overhead cam (DOHC)|
|Assembly sites||Romeo, Michigan, USA / Windsor, Ontario, Canada|
|Predecessor||Ford small-block V8|
|Successor||Ford Coyote engine|
|Compression ratio||9.0:1 (2 valve) / 9.4:1 (3 valve) / 8.5:1 (4 valve)|
|Max power @ RPM (in a Ford vehicle)||390 @ 6,000 rpm|
|Max torque @ RPM (in a Ford vehicle)||390 lb-ft @ 3,500 rpm|
|Cylinder Block||Cast iron / Aluminum (depending on the version)|
We hope you find the 6 Most Common Problems with Ford 4.6L Engine guide helpful. Check these troubleshooting and repair guides for more help on your Ford.