Hello Forum!
You have been a great help so far by me just looking for old threads and getting the info I was needing.
Let me tell you what I've done so far:
2004 Disco II SE- Trail Edition - about 92300 miles.
I was getting the misfire codes for cylinder 2 and 7. I changed the plugs to standard type. The old plugs had little tip left and were around 1/8" gap.
I still got the misfire code. And random misfire code.
I replaced the coil packs. That was a lot of fun- NOT- engineered for way more time to replace than would be needed had they been placed on the sides of the engine! The plug wire are new as well.
I replaced all the plugs with Copper-Top as I thought the tip about using less voltage made
sense. And, BTW- some clown in Charlotte must have already done this job once and replaced the plugs, as two were way too tight, and one (#6) was cross threaded. Luckily only chasing the thread was needed to make the plug go in properly.
So after all this, it sounds like the lifter rod at cyl. 5 is ticking, fairly substantially.
There was no ticking before, just a little rough running with the misfires.
Flushing the engine with the Lucas stuff and changing the oil did not help. The oil was pretty clean to begin with.
Now I am hearing what sounds to be air coming from the motor in the pass. side front (#2-4 cyl.
area) of the engine. It started about two weeks after the oil change. Mileage and speeds were low, probably no more than 300 miles and no faster than 55mph. No change with or without air-conditioning on.
I tested all around the plugs, the valve cover, the secondary air solenoid and can not find air escaping. It sounds like air- it could be worse?
I now get the P0152 code- I can not seem to determine where the sensor would be using the D2
Workshop Manual.
We do no off-road or trailering with the vehicle.
I sure hope fixing this can be done without removing the engine! I can't afford a mechanic. I've been working on my own vehicles since 1972.
Thanks for your help in advance.
Mike

 

P0152 translates to
" Front sensor RH bank short circuit to battery supply" for O2 sensors.

O2 broke off exhaust pipe?

Air noise from SAI pump (unplug pump or remove fiuse) - but SAI should only run for short periods when cranked up cold. From RAVE:

The ECM checks the engine coolant temperature when the engine is started in addition to the elapsed time since the
engine was last started. The engine coolant temperature must be below 55

NOTE: The ambient air temperature must also be above 8

Also, depending on the long term 'modelled' ambient temperature determined by the ECM, the minimum elapsed time
required since the last engine start can be up to 8.25 hours. The period of time that the SAI pump runs for depends
on the starting temperature of the engine and varies from approximately 96 seconds at 8

 

I found the leak- under #6 cylinder head- leaking through head gasket.
Very odd that for no good reason the engine would start a lifter rod knock at the #5 cylinder and a week later the head gasket leak at the #6 ! Plenty of fluids- oil is clean.
I guess the code was given as the cylinder would suck air in too through the leak! The sensor was fine.
Thanks.
Getting it fixed and selling it!