Here is another crude way to look at it.

 

Here was the picture I snapped when I swapped the coil packs. I moved the cables over one-for-one and then swapped the packs out onto the bracket. Then when I went to reinstall the whole thing back into the Rover, I originally placed it upside down. When I went to install the UIM the bolts didn't line up, so I had to pull the UIM back out and flip the coil pack and cables (rerouting, not re-ordering).


I went back out and traced the #8 cable (passenger side rear, correct?) and according to the diagrams it should be correct. So maybe I didn't completely mess it up. I cleared the codes and took it for a quick spin, when I returned it had 2, instead of the previous 7. The codes were still P0308 and a P0314 (pending).

So given that it has error on multiple misfires, I'm not thinking its just a single wire. I have the Pending 0314 for the B1S1 O2 sensor. I also dug into some of the iCarsoft data streams, and some things stood out to me:

Short Term Fuel Trim (B1-S2): 99.2%
O2 Output Voltage (B2-S1): 0.025V (while all others were close to .450V)
O2 Output Voltage (B2-S2): 0.070V
Short Term Fuel Trim (B2-S2): 99.2%

I'm not really sure where to go from here? The Pending code is for B1S1 O2 sensor, but the low voltages are coming from Bank2.

 

I would go ahead and replace both upstream O2 sensors. Your fuel trims will probably resolve after the O2s start giving proper readings.
You may start to get codes for other parts of the emissions system after doing that. I had to change my MAF and purge valve as well -- they weren't showing up because the O2s were throwing off the readings for everything else.

 

For something that was working fine before this job, a pair of O2 sensors stings the wallet.

Edit: I've been thinking, why would the tests pass in iCarsoft? They only test that failed was the Maximum Sensor Voltage test. Just curious, could the engine block ground affect that? Since both banks Fuel Trims are high, I just don't know if its component failure. Is there anything I can test/check before just dropping $75/ea on the O2 sensors?

 

Okay, deep breath ... Exhale ...

It's true a bad upstream O2 can cause misfires despite what a long ago, long time contributor said here. It happened to my truck.

But if that were the problem you'd likely have more than one misfire on Bank 2, i.e. other evenly numbered cylinders would be misfiring. In my case I had misfires on 2, 6 and 8 that appeared at the same time. It was unlikely all three of those wires or plugs failed concurrently. I replaced the Bank 2 O2 and all was good.

In your case your misfire is either 8-only or both even and odd with your iCarsoft. In neither case are problems with the O2s indicated, in my opinion. It's unlikely both O2s failed at the same time.

Let's go back to number 8. Have you swapped wires with number 7 to see what happens?

Remember, always diagnose starting with the most simple solutions and work your way up.

 

Okay, you're right, deep breath

It just started pouring rain after work, I'll swap the 7&8 wires soon as it lets up. I'm hoping I can remove those wires individually instead of tearing out the UIM to get to the coil pack.

 

Yes you can. Especially if your truck doesn't have SAI and you have girly-man hands like I do.

I said it was a PITA and it is but to me your symptoms point to a problem with the #8 ignition wire.

If like me and others you lie face down on top of the engine on top of a quilt or some other pad to do the work I recommend you disconnect the brake servo vac line and crankcase breather tube before starting. Ask me how I know ... To disconnect the brake servo vac press IN on the red ring and then pull the vac line OUT.

 

No need to ask, I just found out.

I snapped the crankcase breather connection that threads into the throttle body. So add that to the list. Then I proceeded to pull the 7&8 wires. When I pulled 7, I think I bent the connector, it doesn't look as much 90* as the easy-to-reach #8 wire. Either way my small hands couldn't manage to get the #8 wire in the #7 position.

With lightning coming in I decided pulling the UIM will have to wait. Since I have to wait I may as well go ahead and order the wires (along with that crankcase breather connection). The question is should I purchase a new #8 wire alone, or replace the whole set?

 

It's up to you about the wires but you can replace the breather connection with one made of brass from the plumbing department at Lowe's or Home Depot for under $5. Just use some Teflon tape before installing it.

 

" The question is should I purchase a new #8 wire alone, or replace the whole set? "

PLEASE, if you have to skip lunch for a few days to save up some money, DON'T waste your time/money replacing only 1 or 2 wires! Get the complete set, and for STI 721 @ this price you can't go wrong > https://www.fcpeuro.com/products/lan...e-rover-hls103

If you decide to replace the O2 Sensors (@ this mileage probably a good idea), Rockauto has BOSCH #15175 (Upstream) for $54.79 each and BOSCH #15630 (Downstream) $46.99 each. OR NTK #25623 (up) for $48.79 and NTK #25624 (down) for $45.79 each.