You don't seem to have ruled out vacuum leaks or loose/corroded ground connections.

 

Can you expand on this?

 

As an example, if your fuel trim indicates that one bank is being fed 20% rich, while the other is -2%, the 20% bank has a problem with fuel delivery on one or more cylinders. If a bank is being trimmed lean(say -15%), you have a problem with unburned fuel going to the cats, and likely an ignition problem, or a sticking injector. Any trims between -3% and +3% are pretty acceptable/normal. The closer to zero, the better, obviously.

Long term fuel trim is more useful than short term here. Short term will register spikes in response to throttle application, which are useful for certain diagnostics, but not misfires like OP is indicting.

When I'm looking at diagnostics like this, I just use the Torque Pro app on my phone to graph real-time, then export for later comparison/analysis on the desktop.

 

Very helpful for future reference! . Thanks!

 

Pull 5 & 8 in the morning before startup.
smell them
taste the tip.

ANTIFREEZE SMELL AND TASTE??

 

I am wrestling with the same issue, 2004 Disco 2, 125K miles. It seems like each thing I try makes the situation a little bit better, the biggest impact I got was from replacing the MAF. I ordered an after market part off of Amazon (believe it or not) and it was only $35. I figured if it didn't help I'd just put the original back on and keep it as a spare. The new MAF dramatically improved the hesitation. I'm still getting codes, but I feel like I'm 90% to a solution. I had cleaned the old MAF twice and it looked fine, but it was not.

 

What codes are you getting? That will help the forum make some edjamacated guesses.

 

UPDATE: I pulled all the plugs and tested the compression. Cylinders 5 and 8 are VERY low. I couldn't even get a reading on cylinder 5. Looks like it's time to check out the head gaskets. I've also had a slow coolant leak for a few months and could not find out where it was going. Guess we'll find out soon enough. I'm gonna start tearing it apart. I'll update when I find out WTF is going on.

FYI for a previous post... The vacuum tubes are all good and I replaced the battery/starter leads last year.

 

Oh dear.

If you are losing coolant, don't see any on the ground, have low pressure on certain cylinders, and have rough starts in the morning, you almost surely have a head gasket leak (I won't even mention the other possibility). You will probably find that 5 and 8 are your cleanest cylinders (having been steamed cleaned). You should be able to tell that by comparing those spark plugs to the others or raising those cylinders and peering in through the spark plug hole. But, regardless, with super low compression the heads will have to come off ) (because the components of compression are rings, valves, and head gaskets--and no cracks anywhere--none of which can be examined and fixed with heads on), which means that you will have to replace the head gaskets (can't be reused) and head bolts (I have reused them but everyone else says that's a no no--I got ARP studs so I didn't have to lie about buying bolts).

Do you have SAI? If not, you can be staring into the cylinders in full sunlight in a three hours or so with tools handy.



Okay, I just registered "I'm going to start tearing it apart," so you don't need any encouragement! HAHA... Oh well. GOOD LUCK!

 

Me too!