I have read through the pages here and Landroversonly.com to see what I can dig up. It seems that there are a lot of conflicting things that it could be. I have these codes right now. I have replaced the filter with a paper filter, I have replaced the top of the air box (it had a crack), I replaced the MAF O ring, and I have inspected all of the vacuum lines and connections. I have no problem buying the MAF if that is the problem. I am also getting an occassional 303, 305, 1300, 300. I know those are all misfire codes. I have new champion plugs (proper gap), and Kingsborne 8mm wires. I just did an oil change 300 miles ago, Mobile 1 HM synthetic. I marked my coolant res to make sure I am not leaking. I have not lost a drop in a 1000 miles or so. Any thoughts on what my next step should be.

 

could be a leaky valley pan gasket...is the passenger side 02 coated in oil?

 

Drivers side is oilly. 3 and 5 are in the center of drivers side. Would that or intake manifold gasket, or valve gasket cause that?

 

I just had the 1171 and 1174 codes after changing plugs and wires. It turns out that the plastic connector at the plenum for the breather hose from the valve cover was broke. I guess I broke it while changing the wires. I replaced the connector and the codes went away.

 

I had to fox that after the same situation. I will double check my connection. I replaced it with a metal connector. It is a little bigger that previous.

 

Checked all the wires last night. No sparks. I pulled the plugs and the look normal, no liquid, not extra or under worn. I can post pics if you like. I wiped down the engine a bit to remove some oil residue and age. I do have a leak on the valve gasket on that side. Could and intake gasket, valve gasket, cause those misfires? Could it be a head gasket without a coolant leak? Should I worry about a block issue on 3 and 5, liner, sleeve, crack? I personally have never had an overheating issue. I can not attest to the 120k before I got it. They did do the HG at 95k. so about 40k ago. It had a paper filter in it when I replaced it to the new paper filter. I also check the other plugs and gaps. They all look the same.