I had a huge coolant leak, as in all the coolant came out at the lower intake manifold gasket. Finally got around to getting that put in. Disco started right up along with the 'service' light.

Symptoms now include:
Once the motor is warm there is a knock at idle, also seems to idle a little low and rough. This knock goes away as the revs increase.

The truck sputtered at about 50mph pretty badly where I thought it was going to die. It didn't, went to a gas station, checked under the hood, didn't see anything obvious. Drove to closest auto zone.

Got these codes:
P1884 - No DTC
P1300 - Ignition Timing
Misfire cylinder 3,5,6,7
P0130 - o2 sensor
p0112 - Intake (didn't catch the whole description)
P0103 - Mass air flow sensor

Drove the truck home, now I'm ready to get it 100%

 

Sounds like your plug wires are crossed. Did you reconnect the grounds on your coil packs? And change your oil? The P1884 wont go away till you get the P0103 to go away by replacing your MAF.But the P1300 combined with the mifires tells me you should check your coil packs. The P0130 might go away after the others are taken care of.

 

Plug wires are in the correct locations. Fresh oil with rotella. Still getting the tapping/knocking noise once the motor is warm. It sounds like its lower in the engine, and once the motor is warmed up the noise will get quieter if you let it sit, but as soon as you try to move it gets louder again. Could it be a slipped sleeve? Or what else could it be? It has to be some motor internals here. What am I looking at to get this thing back on the road?

 

Low and loud sounds like rod bearing, you may be able to isolate which one by dropping off spark plugs one at a time (no explosions in that cylinder makes the round trip up/down a cake walk). Maybe check oil PSI with manual gauge.

 

I don't know if this is the season for P1300 codes, but that popped up for me on the way home today as well as a Cylinder 4 misfire.

 

If you dont change your Mass Air Flow it wont run right and you'll get misfires galore. Youll also still have the P0103. I'm speaking from very recent past experience. I changed my MAF and got rid of not only the P0103 but mymisfire codes as well. Why not at least start with the cheapest thing first? I got my MAF for $35 not a genuine part but i dont really care about that.