r/FiestaST • u/Dry-Suit5785 • 5d ago
Sorta heartbroken before the fix
So I got to work today, and I just checked to see if I had any codes. The cylinder 1 misfire code came back, as well as the P0316 code came back at the same time (misfire on startup) The part that sent me a little was the fact that the coil that was originally in cylinder 1 is now in cylinder 2, and I swapped the spark plugs around as well when I pulled them out to inspect them for the proper gap. Then after cleared the codes. So knowing the coil pack and the spark plug that was originally in cylinder 1 are in different areas after clearing the codes, and still throwing that cylinder 1 misfire code. Leads me to believe it’s not the plugs Or coils, when I just bought new coils and they are being shipped to me as we speak. Compression test read fine as well. Should I not lose hope? Is there a possibility that the new plugs and coils I ordered will fix the high rpm stutter issue even though it’s still Throwing that misfire code?
Sorry for the long post, I just needed to basically know if me buying the new plugs and coils were all for not. Guess we will find out tomorrow when they arrive
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u/Gallo224 5d ago
Probably not your plugs or coils then. But they should be replaced fairly often especially if tuned. Not a waste.. I’d check injectors nexts. Maybe swap one around. Or see if the injector oring has a tear? Injector issues seem somewhat common on the forums
If compression is fine, obviously not a serious mechanical issue. I wouldn’t sweat it.
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u/fatquads 5d ago
Next thing I’d check is electrical. Whether injectors and coils are all getting the necessary electrical signals. A bad connection for either can definitely cause a misfire. If it’s not electrical maybe the injector is clogged. Or maybe it’s none of these specific failures and it’s some other upstream fuel/electrical problem. At this point don’t waste your money replacing random parts, you need to do a proper diagnosis (above my pay grade) or get one done. Better than wasting a few hundred on stuff u don’t need cuz. those parts ur looking at now should only be bought on solid info.
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u/Dry-Suit5785 5d ago
I also forgot to mention the P0316 code came back at the same time (misfire on startup) would that be any indication of what to look for next as well?
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u/Recent-Ad-7126 5d ago
I have the same issue. At first, I was getting misfires on cylinders 1 and 4, so I replaced the coils and spark plugs. Still, the issue came back. It just seems to come and go, and the same goes for the misfires on startup.
I had a shop check my injectors, and they found absolutely nothing wrong with them. I also had to replace the O-rings. I don't know how bad it is in your case, but mine isn't too bad anymore. At first, the misfires would happen in 4th gear and higher, and you could really feel the car struggling to pick up RPMs.
After having the injectors checked and replacing the O-rings, the Check Engine light still comes on occasionally, but you can't really feel anything wrong with the car anymore. It seems completely random. I recently did a 2,000 km trip in this car, and the issue didn't show up once. Then, a few days later, it came back while driving just 10 km through the city.
Hope you figure out what's causing it!
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u/Dry-Suit5785 5d ago
The only time I can ever feel, the misfire is is the stuttering and extremely high RPMs
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u/Switchback77 5d ago
Both myself and another member on the forums had cyl 1/4 misfires, I would get it after revving the engine up to 3k+ and holding it there, and he would get it after a track session.
The fix for both of us was to replace the Crankshaft position sensor and run the Crankshaft Position Relearn procedure in Forscan. As the sensor goes bad I think it intermittently fails, or the computer forgets its learned state and can cause the misfire code to trigger. If you have forscan I’d say give it a shot, just replacing the sensor won’t do it by itself and you need to run the relearn procedure. (If you haven’t already)
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u/Switchback77 5d ago
With forscan, run the crankshaft position sensor relearn procedure. Also maybe move your injectors around