98 Discovery 1. I found several large rats nests in the engine bay on top of the distributor, under the brake booster, and on the front of the engine, and there were several chewed off wires woven into the nests along with big sticks, moss, paper towel, and hundreds of acorn shells.


Two white wires were from a right side injector, a blue wire was from the trailer brake wiring, and two pieces of a small black wire with blue trace were not from any wiring I could find. The rat also chewed off a vacuum line coming out of the firewall on the left side.
I have repaired/replaced the chewed off injector wires (does polarity matter on the injector?), spliced the trailer brake wire, and connected the chewed off vacuum line from the firewall to the cruise control actuator (took a guess that that's where it should go), but could not find anywhere the black with blue trace wires came from. After repairs the engine started but had almost no power and a lumpy idle. Checking OBDII codes I have P0451 (Evaporative Emission System Pressure Sensor / Switch Range / Performance) and P0304 (Cylinder 4 misfire). I read that the fuel pressure switch is back on top of the fuel tank, and all the wiring and hoses on the "advanced Evap System" appear to be intact.
so...1. Does the vacuum hose coming through the firewall go to the cruise control actuator?
2. Does it matter which injector wire goes to which contact in the injector connector?
3. Any idea where a small black with blue trace wire may have come from?

The vacuum line from the firewall

I checked my photos of replacing the fuel pump and there are no black with blue trace wires at the fuel pump so I assume they came from somewhere in the engine bay..

 

I found part of the problem. The rat had eaten off half the wires on the underside of the coil pack, but the kicker is that none of these are black with a blue trace so I still don't know where it found that wire. Does anyone have a photo of the underside of a 98 coil pack so I can use it as a guide to repair this one?



I also found an eaten off vacuum line on a white T under the coil pack and I don't know where it came from. Perhaps from the vacuum line that comes through the firewall? I just don't know, and I can't believe that I didn't take a photo of the coil pack underside when I had it out 7 years ago to replace the O2 sensors that connect under it.

 

What a sorry state of affairs!

Looks like the red coil primary wires are common to all four coils, so you were running on only 4 cylinders. Then just match the other colors together.

For the Tee, that is for the cruise control. It needs to connect to the vacuum pump up front under the air filter or bottle jack storage spot. It won't effect engine performance.

The code for the Evap Canister pressure switch might be a clue about the black wire with blue stripe. Good luck!