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I noticed that my engine was intermittently "missing", as though the spark plug was not always firing. I took off the engine cover and found that 2 of the wire bundles leading to the spark plugs had their wrapping worn off, and I could see bare wires on a few of the wires. The wires are multi-strand and some of the strands were completely broken. I suspect they were rubbing on the underside of the engine cover as it was only the top-side of the wires that was worn down. I spliced in some new wires temporarily (shown in the photos) and that seems to have resolved the misfires. I'm trying to find the part number for that wiring harness, but I haven't had any luck. Does anybody know the part number or distinct name that I would search for to find information online? Edit : 2010 Ford Fusion Hybrid Thanks!

I've been chasing some misfire codes for a few weeks now. My car is a 2010 fusion hybrid with 166k, the codes stored vary between P0301 and P0300. I additionally see P0300,P0301,P0303 as soft codes that clear when the vehicle is shut off. The misfire appears to only happen during idle when the car is already warm. Mostly when I am sitting in the vehicle with the heat going and the car calls for more heat so the ICE kicks in. If i start driving, i can feel the hesitation quickly clear up. I have searched these forums and google for keywords i felt would be relevant but was unable to find anything that matched. troubleshooting done: Isoheet added to half tank of fuel and topped up with premium gas from a different popular station New motorcraft plugs (5000 miles ago) Measured coil pack resistance all within spec to each other,during trouble shooting i additionally swapped coils 1&2 and 3&4 to see if misfire codes would follow (they did not) measured injector resistance, cyl 1&2 11.2ohms, cyl 3 14 ohms, cyl 4 9.6 ohms - note all injectors have oily/gas wetness on connector. Harness, and fuel rail connections are all bone dry. Visually inspected balance of connectors on harness - everything dry and clean. listened to injector firing (1&3 have a different sound but do fire - see below) Removed & Cleaned throttle body & wiped out intake of major grime Flooded intake area with map gas to check for intake/vacuum leaks - no surging or smoothing head temp sensor visually inspected - clean/dry connector Today I checked the new plugs and piston tops again to see if there was any visible damage. Cyl 1 had a clean spot on the piston but, 2&3 were normal, i did not check cyl 4. Besides color differences, all pistons were dry. All spark plugs were dry and near identical color/gradient with the exception of cyl 2 which appeared to have a little blow by so i assume that was slightly loose. I had intended to replace all 4 injectors due to the residues on the connectors and varying ohm readings, but then I noticed today that Cyl 1&3 injectors stop and start firing at the same times (when engine runs rough) which brings up so many questions. When they do fire, they have a slightly deeper click compared to injectors 2 & 4. I tried calling a local dealer and asking if there were any reason injectors 1 & 3 would stop firing or if there were any TSB for ecm/pcm updates etc - they were not very helpful. I will be back probing the injectors tomorrow to see if they are getting power when they stop firing, maybe they are both sticking and its fuel pressure related or something - seems fishy. Any advice is greatly appreciated. questions: -Would the atkinson cycle (or any other FFH programming) tell injectors 1 & 3 to stop firing at the same time? It seems odd that the engine would try to run on 2 cylinders, or that both injectors would intermittently work simultaneously. -I understand this is a coil on plug design and direct injection, but would cyl 1&3 have any other electrical commonality that i can check? -Does sync reside in the PCM? I have random sync problems (latest version installed) that require a reboot for bluetooth to function properly - electrical problems? related? -Should I replace all the injectors due to the wet connectors and clean the harness with connector cleaning spray before taking it to a shop? -Any other advice on things to check before i bring it to a dealer?