engine misfire replaced spark plugs and coils still misfires
What codes are you getting, in the form P9999?
What engine, how many miles, is the check engine light on?
As @Mustangman asked previously… Those answers are key to trying to diagnose. Its raining today so I dont feel like looking it up… I know, Im horrible, but I’m OK with it.
compression check on all cylinders
hook up vacuum gauge at idle and report results
injector balance test with scanner and fuel pressure gauge . . . all should be the same
hook up noid lite to each injector at idle . . . are they all being pulsed the same?
any obvious rat damage to injector and/or coil wiring?
there are many possible causes of misfires, as you can see . . .
Knowing which diagnostic code(s) are stored in the engine computer will make this problem easier to diagnose. The codes will differentiate between a single cylinder misfire vs. a misfire across all the cylinders, and that’s a big clue to what’s wrong.
I have had to repair many a Dodge pickup with the 5.9L V8. Those engines are now well known for timing chain stretch… When the T chain stretches it throws off the firing order to such an extent that it will throw misfire codes all over the place. Until the T chain is replaced there is no other action that will stop it… if the chain is stretched. Apparently those chains would stretch with as few miles on the clock as 60-70K.
Its a real thing…
Having so many reports of chain stretching… with a thing which was marketed to last a lifetime of a car… it is not a surprise some manufacturers transition back to T-belt
A friend of mine just recently bought VW Golf with a new 1.4 Tsi, where apparently some “strengthened” T-belt guaranteed for “lifetime” and the justification from VW is that it eats up less energy for friction and produces far less noise. Marketing department reversed direction ?
The actual issue was that they used a single and simple roller chain… not the typical “multi-link” style chains that typically last the life or near life of the vehicle.