So, I have just done the 3 Amigos fix (Opt B) and was quite happy that my dash was light free. WELL for an hour or so.... ugh!!! Now the engine is running rough, and throwing the code P0300, P0307.

I am running the ultra gauge, so I reset the code and it comes back right away. My vehicle is '02 Disco 2 with 154,000 mi and the HG is leaking (just bough all the parts to do the job). I pulled the plug for #7 and it is dry and I don't see any moisture in the cylinder.

I was hoping for some help to diagnose... my thought is I have broke / disconnected some line / connector. Where should I start? Or could this be a catastrophic failure of the HG?

Thank you

 

Sure you could be mixing coolant and exhaust.
I would want to check out plug wires first

 

Thank you dusty1. If I did have a major failure... would I be able to test for it? Since I am going to have to pull the upper intake manifold to get at the wires / coil pack. I did pull the #7 wire and run the truck it made no difference. SO I am thinking either I pulled a wire or there was a failure somewhere.

A weak battery wouldn't do anything like this would it? Also wondering if doing the Opt B mode would have caused any issues? I will dig into this tomorrow, see if I can figure it out.

 

coil
wire
plug
injector
you would need to molest one of those, while doing the brake fix, if they are connected.


yes you can get a tester for exhaust//coolant mixing.





or a pressure test on cooling system would let you know if you are flushing it out.

 

Headgasket failure may exhibit rough idle at cold start in the morning.
usually cylinders 1,2 7 or 8.

If you replace all the wires and plugs and still have a rough idle after cold start
you may be facing HG replacement.

Betting at 154,000 you are facing the 2nd HG replacement - the first of which may have happened at 80,000 to 100,000 miles.