Thanks for giving it a look EXTINCT; keep in mind that I noticed P0306, along other codes, during that particular trip -it is the cylinder (6) that I used to swap plug from 5 with. FYI, I cleared all codes the following day (Sunday), and those particular codes had not come back up yet, so I'm hoping it was just a hiccup; only P0305 comes back immediately and is still present, reason why my focus is on it, and you've already suggested to swap wires to keep troubleshooting.

To answer your question, no, lower intake hasn't been off; I haven't requested any job needing the removal of it, as far as I know; only the upper-one a couple times for easier access to the coils and replacement wires, and to replace valve cover gaskets; last time back in Oct-Nov 2021. Either way I now do hear a hissing sound as I drive. As per injectors, none have been played with during my tenure -not sure if when trying to troubleshoot the "crank-but-no-start" issue back in 2021. I do pour a bottle of Chevron Fuel Treatment every time I change the oil.

(TIP: from your comment: "always runs lean except occasional jumps to rich" ...so when the needle moves towards 0 it means running LEANER, and RICHER towards the opposite, correct? ...just trying to learn how to better read these dials) ;-]#

Thanks again for your time and effort, it is greatly appreciated.

 

Yes, .9 v is above 14.7; .1v is below 14.7. Narrow band 02 sensors are basically a switch and ecu manages AFR by cycling between rich and lean. Yours stays lean and the randomly switches rich, so at least the 02 is good. Normally you can test with stone cold startup because a Disco is rich for startup only, then after a few seconds it switches in to closed loop and starts cycling. Lean is likely a vacuum leak, but usually those are not isolated to one side unless injector o-rings are leaking and that is usually only at idle because small vacuum leaks are inconsequential on the highway when injectors are running at 30% duty cycle. Rich can mean misfire while loaded or maybe leaking injector at idle, but leaking injector is usually inconsequential at 30% duty cycle.

 

I’m assuming that you cleared your previous fault code with your OBD2 reader. Otherwise it’s possible that you fixed the fault but it is still logged.

 

...you assumed right; everytime I try a fix, I clear the codes and go from there. ;-]#

 

..:: UPDATE ::..

So took the time this morning to finally do the wire swap and keep troubleshooting. Decided to follow the long-proven method of removing the upper intake. After removing it, I saw that upper side of gasket, and lower face of intake pretty wet, and I do not recall seeing them wet in previous removals, just not sure if this is normal or a sign of some other issue. See pics attached at the bottom of write up. I also found that coil pack plate was left unbolted, so it was free to move a bit within that space. I checked all wire plugs in case any was loose, but no; so, went on to swap cyl 5 wire with a used one I had -it came from a new set with very low mileage that was replaced back in OCT-NOV 2021, but I'm pretty sure it is OK. Put everything back together, secured coil pack plate with the 2 lower bolts to ensure it did not move; wiped clean the upper face of intake gasket and lower face on upper intake, bolted and connected everything, including battery that I had disconnected. Fired up the Disco and it started with no issues; it started right up nicely. Codes had been cleared when battery was disconnected, so did not do it again. Stayed put with Disco running while I gathered all tools to put away; Disco still pretty stable; no solid or flashing SES light, so decided to drive around for a bit; I did feel it a bit rough and shaky, perhaps not as much as before, and a block or 2 later SES light started flashing and stayed solid, in fact, it stayed more solid this time around than pre-wire swap, but it still flashed at times. Check the codes and P0305 was LOGGED again, as well as PENDING, along with P0300, but I will not care for pending codes, just the "LOGGED" one (P0305). So, after swapping cyl 5 plug with cyl 6's and replacing cyl 5 wire the issue still persists -P0305 code present, a bit rough and shaky, especially when giving it gas. I will not be driving it anymore today, but tomorrow I'll clear the codes again and will take it for a longer drive to see how it behaves, but I'm guessing P0305 will light up again. Please advise where I should look into next to keep troubleshooting.

Besides the pics at the bottom, I'm adding a couple videos: one right after removing the upper intake so you all can see the state it was in, the other after firing it up after putting everything back together, let me know what you guys make of the noises you'll hear, take a look at crack on sleeve near nuts of throttle wire, how wet steering box looks, the way fan wobbles since it has a couple broken pieces and battle scars, and anything else you may kind enough lay your eyes on! ;-]#



Happy & Bountiful Thanksgiving to you all!


See the small puddle on inner lower lip.


See how wet it is on inner lower lip.


See how wet it is around the intake holes.


See how wet it is the upper face of the gasket, and how dirty the 4 closest intakes to the front.

 

Do you have pcv mod done? That might explain oil in intake if not. As far as troubleshooting, now swap left coil with right coil.

 

I had to look that up to respond, but from what I read and saw in a Best4x4 post I do not think so; however, the way hose from passenger cover connects to upper intake in my Disco looks pretty much like in pic below from Best4x4's post, and I do recall replacing the plastic oil separator in passenger cover a very while back, so I'm guessing no full PCV MOD on my truck.



As per next step -coil swap; I feared that being the next step. But I'll gather myself to do it asap. Anything else I should look into while disassembling upper intake once more?

Thanks again!

 

Take that PCV hose off valve cover and check to make sure baffle is not in there, then take off opposite end and see what is under the hose, post pics or compare with best4x4

 

I'll check, but "baffle" must be there, I put it in myself when I replaced valve cover gaskets; but since they were also replaced by a mechanic back in oct-nov 2021, I'll check to see if they removed it. On other end is a metal nipple, but had been there since I had the Disco, just not sure if the one recommended by Best4x4. You recommended me to look into this because of the wetness around the valve covers, right? The recommended mod will prevent this much wetness? Let me know, thanks.

 

If I’m understanding Extinct’s post correctly, I think he means the baffle inside the valve cover. I think he means that it should be there. If I’m wrong, please clue me in.