So I used my truck to pull out some old fencing a redneck a**hole put in at a house of mine and it did amazing. I drove home and had no problems. I took the family out to get a Christmas tree and noticed and a vibration at the stop light. I finally got a code and it was p0304 cyl 4 misfire. I checked the spark and it was great. Pulled the plug bone dry clean. As I was checking the spark and put the plug back in and ran the truck. I then pulled the plug to check the gap. Should the plug be wet with fuel as there was no spark? I’m thinking so and that may point me to a failed injector.

Any thoughts on this?

 

could be just a bad wire....how old are they ??

 

They are about 2 years old. I put a new plug in and still same issue. I going to change the wire and go from there.

 

So an update. I replaced the wire and took it for a spin. Same issue. Long story short I found the year old injector to be clogged with rust from the fuel rail. So my day was spent cleaning the rail and all the injectors.

 

I thought I had resolved this p0304 code but it has popped it nasty head up again.
codes I’m getting:
p1157 oxygen sensor problem with switching rich
p0304 cyl 4 misfire
p1316 misfire causing excessive emissions

what I have done: new plugs, new wires, coils all are 2 years old. Tested all injectors, fuel pump new within the year along with new filter.
the crown of the piston in cylinder 4 is clean. Don’t think it’s a head gasket as the water ports are on the ends of the heads. I did a total rebuild of the engine 2 years ago. Run like a champ until last month.

any ideas?

 

are you using / losing coolant ?
you could still have rust in the fuel rail ( been there) how did you clean the inside of it ??
try switching the injector with a different cylinder to see if the problem follows it
the 1316 can be due to the 304
how old are the o2 sensors ?? it "shouldn't" affect just one cylinder ..........but this is a Rover
runs some BG44 or Techron or Seafoam cleaner through the fuel system and drive it like you stole it for a while....
what plugs are you using ?>>>>>>dont use expensive ones, they arent neccessary RN11YC champion or BPR5ES-11 NGK are all thats needed, and make sure you use some di-electric grease on the boots

 

I have not noticed any coolant loss nor do I smell coolant in the exhaust. I will swap an injector and see what happens.
I pulled the rail and soaked it over night in my parts washer then used a long nylon brush on my drill to clean in out. I guess it still could be some crap in the rail.
O2 sensor are right at 2 years old.
Cheep NGK plugs is all I run. I have not put any grease on the boots, I will do that.

 

I pulled cylinder 4 injector and swapped it with cylinder 2. I did a dry compression test and I had 110ish across all cylinders. I will see if anything changes. If not I will pull the coils swap another one in.

 

Well still having the same problem. Swapped injectors changed coil pack with one from parts shelf and no change. I have an o2 sensor on the shelf I may swap out the front one but I don’t believe it would cause one cylinder to be messing up. I did notice on my test drive the cooling hoses are very tight. I’m wondering if I do have a head gasket leak.

 

So update time:

I changed to another o2 sensor no change. Had my inspection plate off when I pulled out all the fencing and forgot to put it back on so I checked all the reluctor ring tabs. All good. At this point I figured I had an electrical problem. Pulled the computer and ohmed out all the injector wires. All good. No change. I pulled a computer off the shelf installed it and drove like a fool and the misfire never showed it’s head. So bottom line for now I believe it was the computer.
So I now have a head gasket kit and arp studs to put on the shelf until the next rebuild.
Thank you for all your ideas and help.