2005 Infiniti G35 P0300

Does the code P300 come back as soon as you clear it?

It blinks first then goes solid

So the engine runs rough all the time?Do you have a scan tool that can read which cylinders are miss firing?Some scan tools have what's called a miss fire graph/missfire counter.

Runs rough at idle and and when in gear. I do not have such a tool. I did ohm each coil. #1 cylinder coil measurements were much less than the others so I replaced that one, no change. I thought maybe I had crossed coils but the leads will not stretch correctly

Let's do this while its idling rough unplug one coil at a time and see if it runs rougher?Then plug it back in and go to the next one and see if it runs rougher?Makes notes of the cylinders of the coils you unplug and there is no change?

Ok, it will have to be tomorrow though. I have ordered a complete set of coils (6). Can I get back to you tomorrow?

Yes you can but I highly doubt all of the coils failed at the same time.not to mention that would be expensive to replace them all.

Isn't it odd that any of them went bad just from changing the plugs?

That would be really weird I have seen bad plug boots that were old and brittle and when you change the plugs that's the end of them.Did the start from you changing the plugs?

Yes it started after changing the plugs. Ok, I had already ordered a replacement set of coils. Just put them on tonight. Still have miss. Check engine light will flash for a bit and then go out. Could one of the wires have broken on the plugs going to the coil? If so, how do I check that? I am sorry for the delay, work kept me from being able to do anything with the car.

Have you changed the plug boots yet?Like I said before I would suspect the okug boots before the coils.Did you try what I suggested unplugging one coil at a time to see if it runs different?

The new coils came with the new boots already attached. I noticed when putting them on tonight it was a much tighter fit. No I did not take each plug off as I new I was replacing all of the coils. Is there anyway to tell if the plug is bad going to the coil? Like a broken wire?

The reason I asked you to unplug one coil at a time to see if it runs any different was to see which cylinders weren't contributing so we could narrow done the problem.So let's do what I suggested and go from there.