P300 code

Are there any driveability issues?

No, the enine will start and it will drive, but seems a little lumpy when taking off or reversing, pulled new plugs out and found 2, 4, 5 a little sooty, black like not burning fuel.

If those cylinders were dead, you would know it. Did you look at the other plugs, how do they look? You also had codes p0302, 304, 305?

It's possible your system maybe running a little rich?

The other plugs look normal, not sooted.

As far as the system running rich, several things that can cause that. Use a gage and check fuel pressure. See if pressure will hold, with everything off.

Does the preesure not hold true for all injectors & lines or is the banks different, pressure should be approx 55psi - 60psi correct. Reason bing 2 74 are in trh front and 5 is in the back?

Maybe an injector/s leak? Can you erase codes and see what comes back?

I disconnected battery neg terminal yesterday and engine light is gone now, driving this morning and light has not returned yet, I will look at codes again or see if tester still reads misfire cyclinders 2, 4 5. Although orignally it also gave a P0171 code which is MAP sensor or Or sensor? Is there 2 o2sensors on the exhust output? Is it possible either could be bad.

My info shows 171 is a lean code.
172 is a rich code. At the moment, if no check engine lite and no driveability issues, I wouldn't go hunting trouble. Intermittent issues can be a pain to track down.

Yes, the 02 sensor could be an issue, but, without testing, we're just throwing parts at it.