Intermittent rough engine and misfires both in idle and while driving, codes P0305 and P0300

Okay. Clearly if the code for the injector comes back then we have a circuit issue but this matched with the P0300 would make sense if we have some leaking injectors. So replacing all of them was probably a good call.

Agreed. If the injector circuit code is back then we need to run through that testing and find it but I would not be surprised if the injector harness is the issue as I have seen that a number of times on 4.7L.

It is not bad. The manuals don't actually list a process for this however I attached the illustration of it. Just follow the harness from the PCM down over the engine to the injectors. Not much has to come off to remove it as it has the wiring cradles that hold it in place.

Hi Guys,

So in this issue the most consistent part is heat. The hotter it gets the worse it runs, Maybe we are looking at situation that the car is in fact getting to hot but not enough to cause the normal symptoms like the gauge reading hot, steam blowing out and so forth. Did you change the temperature sensor? Do you have or can you get a laser no touch temperature gauge? The type that you point the laser on a surface and can read its temp at the dot. I don't think there very expensive and AutoZone has a good loaner program. Next time you go out and it hot and you have run it to the point that its acting up take a bunch of readings to what you can get well. We want to know the temperatures at the front and the rear of the heads, the water pump, the block and the intake manifold where it meets the head. It's worth a shot to check.
Tom

Good point Tom.

Sounds good. Keep us posted but if 213 is the highest then that sounds fine.

Good Morning,

Where was this 213 temperature reading taken from, the block, the head, etc? We want to see if you have consistency temperature wise around the motor. Checking the inlet and outlet of the radiator is good info to have also. I have seen injectors fail in interesting ways. I had one that the closer to freezing the more they failed. If the temperature outside was 40 degrees it was fine, if the temp outside was 35 degrees one injector would leak, if it got down to 32 degrees 2 of them would leak and below freezing all six would leak. Above 45 degrees the car was perfect all summer long. When I brought them into a place that all they did was injectors the guy told me he's never seen anything like it and his feeling was that at one time the car must have gotten so hot that it ruined them and that he was unable to clean or other wise repair them. When I got new ones the entire problem went away, but it was also a temperature sensitive injector failure.
Tom

Okay, well there is something going on there, 400-500 degrees is pretty hot. Is there any sound like a possible exhaust leak? There might be somewhere in that area an exhaust gas circulating tube that could get that hot, but it would emit enough to make the area hot unless it was leaking. I'm going to see if I can get an image of what I'm talking about. Still though 400-500 degrees is hot. We might be onto something here. From the pic looks like you getting smoke up against the fire wall, Am I seeing that right?
Tom