7.3 rough idle?

meyersracing

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pittsburgh
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21 f250
Do these trucks idle rough? Mine is very inconsistent but never modern engine smooth idle. The idle RPM is always the same but the "feel" from the drivers seat changes, sometimes more rough or broken than others. Kinda feels like a mis is the engine, even sounds kinda funny. Best way to describe is kind of like how an older vehicle acts when theres a vacuum leak or something. BUT no cel and runs like a top otherwise. I seen small mentions on this here but no real info.
 
Mine has had a rough idle on startup since I got it a year ago. Recently it has randomly had a delayed start, doesn’t appear to be weather related. Took it to the dealership and had no codes. I guess I am just going to have to wait until it breaks, just hope it’s not in the middle of nowhere while camping.
 
Have you tried running 91 or higher octane. My 6.2 Raptor hated 87 octane fuel, try a top tier high octane fuel.
Not a bad idea. I havnt tried that yet. I also have yet to install my 5star tune. Im assuming this idle is normal. I havnt been around another 7.3. The dealer didnt have one available, so crossed my fingers and ordered. Other than this goofy idle, loving it!
 
Not a bad idea. I havnt tried that yet. I also have yet to install my 5star tune. Im assuming this idle is normal. I havnt been around another 7.3. The dealer didnt have one available, so crossed my fingers and ordered. Other than this goofy idle, loving it!
I hope that does the trick, as it gets warmer it'll be more prominent. At least that was my case in Phoenix area :rolleyes: (probably a more reasonable explanation, but I hop it helps).
 
Hopefully I don't jinx myself... I have just over 300 miles on mine and you would not know it was running if the tach wasn't sitting at 600rpm.
 
Have you tried running 91 or higher octane. My 6.2 Raptor hated 87 octane fuel, try a top tier high octane fuel.
I have always run 91 non ethanol, can’t get 93 in Colorado, No difference, I ran 93 in NC a couple of weeks ago after the hard start began, Also no change.
 
Check the thread on Massive's plug wires. I changed mine two weeks ago. OEM wires had around 2000 ohms resistance (with one at 2600), Massive wires had 380-390 ohms. Definitely made a difference. Better, smoother power too. Worth the $80 to me.
 
I replaced the plug wires on mine and it does the same exact thing. I am used to performance vehicles with rough idle from the camshaft, but this does not seem like that, not exactly like it is missing either. It is pretty odd and seems somewhat common on the 7.3.
 
There is a TSB on the plug/coil wires.....causing misfires...(at least on the 20's last year)....I would definitley go performance aftermarket if I had a 7.3
 
Massive MSX 90’s ordered we’ll see if it fixes the problem. Rough Idle on startup since day one. Hard startups started at around 20k miles.
 
I replaced the plug wires on mine and it does the same exact thing. I am used to performance vehicles with rough idle from the camshaft, but this does not seem like that, not exactly like it is missing either. It is pretty odd and seems somewhat common on the 7.3.
On that note, these engines do have variable cam timing. I'm wandering if it's a cam timing thing, part of the idle program or some other issue related to cam phaser. As most have noted it sounds quite normal under power and driving speeds.
 
I replaced the plug wires on mine and it does the same exact thing. I am used to performance vehicles with rough idle from the camshaft, but this does not seem like that, not exactly like it is missing either. It is pretty odd and seems somewhat common on the 7.3.
I'm thinking it is more likely slight differences in the fuel injectors. At idle, if they are not exactly the same, the engine would run rough. One or two cylinders might be slightly richer or slightly leaner than the others while idling. Can't prove it, but it makes sense. Mine isn't missing, but it doesn't sound smooth, or equal.
 
update: I ran a tank of 93 octane. No noticeable difference in idle. Still rough. Must not be bad enough to classify as a misfire because no CEL. May try new wires as suggested but this One only has 1500 miles and is probably not the "bad plug wire" problem. I even tried to duplicate a higher idle by ever so slightly adding throttle. Same jumpy idle even at a higher rpm.
 
Do these trucks idle rough? Mine is very inconsistent but never modern engine smooth idle. The idle RPM is always the same but the "feel" from the drivers seat changes, sometimes more rough or broken than others. Kinda feels like a mis is the engine, even sounds kinda funny. Best way to describe is kind of like how an older vehicle acts when theres a vacuum leak or something. BUT no cel and runs like a top otherwise. I seen small mentions on this here but no real info.
Any updates? I feel like mine is the same. Only notice it at stop lights and such.
 
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