Ford Modular Family

All Engines

Backfiring through the intake may be caused by failed catalytic converters, which themselves may have failed from misfires

Vehicles with 2-valve and 4-valve engines: Spark plugs can blow out of the sockets, stripping their threads in the process as well as the threads in the cylinder heads, which requires retapping them. This can also damage ignition coils.
Vehicles with 3-valve engines:
- The cam phasers frequently fail due to sludge and can cause catastrophic engine damage; failing phasers are usually identified by ticking
- The timing chain tensioner can fail, which can cause catastrophic engine damage. A worn tensioner can be identified by a rattle from the engine, especially at cold starts or when letting off the throttle when engine is hot.
- A worn timing chain tensioner can cause the timing chain guides to fail from the chain slapping around, which can result in rough idle, DTC P0300, and/or catastrophic engine damage
- Spark plugs can seize in the sockets and break apart during removal, requiring extraction of about ~1 hour labor per plug. Failure to remove all the spark plug pieces can result in catastrophic engine damage.

MY93-95 vehicles: Valve stem seals can wear/fail, which can result in the engine burning oil
MY96-01 vehicles: The plastic intake manifold can crack, and its rear heater hose fittings and front coolant temperature sensors fittings can loosen and fail, creating a coolant leak
“Early” vehicles: Head gasket failure

Ignition coil boots can deteriorate and cause misfires and/or loss of power, and this may also allow the spark plug wells to fill with oil and/or coolant
Fuel pump driver module can fail due to corrosion and cause the engine to stall. This happens most often at highway speeds, and the most common symptoms are hard/no starting, lack of power, and/or DTC P1233. It is more likely to occur in cold climates due to salt/sand from the road in the winter.
Oil pan gaskets can leak, and on certain F-150 models, these leaks occur onto the hot exhaust, which can result in engine fires
Sensor failures (most common on MY97-02 vehicles):
- MAF sensor
- Camshaft position sensor
- Differential pressure feedback (DPFE) EGR sensors
- Idle air control valve

The 3-valve 6.8L Modular V10 does not suffer from the timing chain and cam phaser issues of the V8’s, as it does not have variable cam timing.