Misfires under acceleration - 2000 Ford Expedition

p0306 is misfire with number 6 cylinder P0306 Cylinder 6 Misfire Detected and p1314 cat converter problem P1314 Misfire Rate Catalyst Damage Fault Bank 2 P1314

Hi Dion:
When under acceleration, an engine experiences increased cylinder pressures. If you have a spark plug(s) that is in poor condition, it can misfire (or not fire) then, so the unburned fuel will ignite in the exhaust, and "backfire".

Another possible cause could be that the timing is not retarding when the vacuum drops under acceleration.

My recommendation?
TIME FOR A TUNE UP
Cheerfuls.

well if engine is ok. No year, no engine stated, wow. !!!
misfire is bad combustion. (gas usa cars are my answers)

1. never did a TUNEUP this decade? 60,000 miles tunes.?
2. bad spark first.
3. bad fueling next too rich causes misfire. lean bogs.
4. misfire shakes engine hard, is it .
5. does it misfire parked just racing engine?
6. cause are many over 50, but if engine good way less, so what can it be (we do tests no Gue$$) bad spark plugs, leaking injectors execessive fuel pressure, bad TPS, sensor. map sensor issues, (even clogged) and others. no engine stated makes waxing smart, hard, way to hard so i quit here.

check the HO2s and HO2 sensors as the tuning of the engine is out because of erratic sensor messages to the ECM. Misfires can also be from faulty injectors or low fuel pressure in the fuel manifold . The rattle under acceleration will be detonation from a problem with the air/ fuel / timing because the ECM is not getting constant readings from the sensors to be able to adjust everything

It seem to happened Only when you turn and go up hill...?
-If so Check plug wire. It might be too lose , broken some where
and spark to metal.

Mai

either you have a faulty gas pump, one or more spark plugs or cables ar going bad or nrrd to br replace, could be a vacuum leak too, yourcar have the check engine light on? if so, need to know what code the will help you a lot.

try some some fuel injection cleaner and check and make sure plug wires are in order

Replace o2 sensor and ECU might need an software update done by ur local dealer.Post by AUTOMOTIVE DIAGNOSTIC FIELD SERVICE South Africa

You should definitely replace the fuel filter though this probably won't fix your hesitation. It wouldn't hurt to replace the spark plugs this is usually the culprit on these engine. I have the same engine in a '99 caravan and found the for some reason the spark plugs on cylinder 3 and 4 loosen up after one year and cause a misfire between 45 and 50 mph under load (when mildly accelerating).

I had to rebuild my engine at 97000 miles cuz of low engine oil pressure and bad berrings