Where to start???? Plugs, Coil Pack, Injectors...
 

GDay Brains Trust....

So after 6 years plus of happy motoring the truck has developed a missfire...
Its a 2000 4.0.

Cant complain, apart from a new radiator and water pump since purchase in 2014 all has been good. Have gone from 120k to just over 200k in that time.

Still pulls like a train with no issues under acceleration, but can feel it regularly whilst on a constant throttle. A little harder to start tho.

Check engine light started blinking for a while yesterday until it warmed up. Came on this morning and stayed on.

So... which first?

Plugs?
Injectors?

And is it worth replacing the coil pack at the same time?

Or is there something else I should consider?

Appreciate your thoughts.

Cheers, Al.

Crankshaft position sensor is my bet. Mine would run like a hairy goat up to about 1200 rpm then be ok, new cps fixed it.

Do you have a coil or the coils on the plugs?

OK on hard acceleration? its normally the other way around.

Another thought...Oxy sensor on the exhaust?

Ah, forgot, I did replace the CPS a while back....

Hmm, worth a look... have a day off 2moz will check.

1. If your check engine light is flashing it means a serious misfire and could cause damage.
2. Check your codes - what codes are coming up?

If you’ve replaced your plugs recently make sure (not platinum ones I hope) they are gapped 0.035.

Have you checked oil for milkyness- blown head gasket can cause misfire.

if the check engine light is on check codes first