P0300//mulitiple misfire

[Ryan Graham]

If you narrow it down to a fouled injector (either by swapping with an injector from a cylinder with no misfires or injector balance test) then I would probably just replace it. I say this not knowing how much an injector for the H3 is, but I haven't had very good luck cleaning injectors. Please keep us informed as to what you find

[Desert Dan]

I'd say it is the cylinder head!

Take it to the dealer and get it fixed if that is the problem.

[Hunner]

Like Ryan said, get them to do a leak down check. That was how they confirmed my problem. They have done several at the small dealership I go to.

[hawaiih3]

Update::

I have introduced the fuel injection cleaning solution in the system, actually several bottles (gradually) and I can feel a better/stiffer pedal. I run the live datastream while I am driving and all cylinders show "0" misfires count. While I let the engine idle I show no misfire count on any of the cylinders but # 3 (before that it was all of them)but I must say that they are very few now, not as before. I believe I just had very dirty fuel injectors(especially #3). Overall engine performance has been great even before I noticed anything, usually with a misfire error the engine idles very rough but not in this case. If I have never ran a live datastream test I would never know there was an issue, usually most folks run a scan to check why the check engine light has come on. I will be keeping an eye on this and see what happens. I am very hesitant to take it to the dealer because I have bad service in the past ( another issue for another day)and I don't trust them and the bad thing is that here only dealer here in Hawaii.

Thanks to everyone with your input.

JJ