Chasing a misfire for 3 days, turned out to be a $9 part

Tbh, I spent a full weekend chasing a cylinder 3 misfire on a 2012 F-150. Swapped coils, plugs, checked compression, everything, and it still stumbled. Finally found the injector harness had a chafed wire hidden under the intake, 30 cents of electrical tape fixed it. Anyone else wasted hours on something this dumb before finding the real cause?

2 comments

2 Comments

ray_miller411d ago

Cmon, you guys are blaming the parts and not the real issue here. Ive been turning wrenches for 20 years and a chafed wire is usually a symptom, not the cause of your time sink. If you had spent 10 minutes tracing the harness first, you wouldve found it in an hour. Instead you threw parts at it because you didnt do the basic visual inspect before swapping coils and PCMs. Thats on you, not the truck. A misfire code on a specific cylinder always points to power, ground, or fuel on that one hole. The $9 part is just what happens when you skip the penny test of wiggling the wiring while its running. Am I the only one who checks connectors before buying anything?

evan_burns951d ago

That chafed wire story hits way too close to home, I did almost the exact same thing chasing a cam sensor code on my old Mustang. Replaced the sensor, the crank sensor, even the PCM before I found a rubbed wire behind the harness bracket, like 15 minutes of work. It's always the stupidest, cheapest thing that makes you feel both relieved and like an absolute idiot at the same time lol.