P0303
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Senior User
Joined: Aug 2011
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From: Central arkansas
P0303
My ‘17 f150 5.0 with 95,000 popped a p0303 code today, says it is a cylinder 3 misfire. For the last couple months it has had some 6-7 seconds cranks and stumbled as soon as it cranks. It only does this after setting 3-5 hours. If it’s cold or just recently been run it cranks fine. Also sometimes when it will idle rough.
Are plugs the first thing to change? Any other ideas?
Are plugs the first thing to change? Any other ideas?
Lead Driver
Joined: May 2015
Posts: 5,889
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From: Mts. S. of San Francisco
With modern ignition systems, the plugs are often the first thing to go. However, it could possibly be the ESC module. The simple thing to do is to swap the ESC from #3 to some other cylinder to see if the problem follows that. If the problem stays with #3, then you're probably looking at new plugs.
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From: Maine, Virginia
His is a previous gen 5.0L built prior to Direct Injection so I think they aren't as hard on plugs as the DI engines.
The problem with just changing plugs is that the boots need to be changed as well. Changing plugs and boots may solved the problem and yet there could be a failing coil on the #3 cylinder.
Lead Driver
Joined: Dec 2016
Posts: 5,650
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From: GA
My ‘17 f150 5.0 with 95,000 popped a p0303 code today, says it is a cylinder 3 misfire. For the last couple months it has had some 6-7 seconds cranks and stumbled as soon as it cranks. It only does this after setting 3-5 hours. If it’s cold or just recently been run it cranks fine. Also sometimes when it will idle rough.
Are plugs the first thing to change? Any other ideas?
Are plugs the first thing to change? Any other ideas?
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Senior User
Joined: Aug 2011
Posts: 240
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From: Central arkansas
Thanks for the help, We’re at the in-laws this weekend and my CEL came on as we were pulling up. I’ll go ahead and grab some plugs this morning and change them before we leave today. I’ll order my coil packs from white bear lake ford and they should be here end of the week. Hopefully this will solve the problem.
about a year ago I changed the plugs and coil packs on my wife’s edge and I had a hard time getting the coil to come loose without ripping the boots. Is there a trick to that or was it just because hers were nine years old?
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Lead Driver
Joined: May 2015
Posts: 5,889
Likes: 360
From: Mts. S. of San Francisco
Thanks for the help, We’re at the in-laws this weekend and my CEL came on as we were pulling up. I’ll go ahead and grab some plugs this morning and change them before we leave today. I’ll order my coil packs from white bear lake ford and they should be here end of the week. Hopefully this will solve the problem.
about a year ago I changed the plugs and coil packs on my wife’s edge and I had a hard time getting the coil to come loose without ripping the boots. Is there a trick to that or was it just because hers were nine years old?
They can get cooked on, so to speak. Just be gentle and persistent and they will come loose.
And yes. ESC = Electronic Spark Control AKA coil pack and a few other names.
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From: Central arkansas
I picked up some plugs today and changed them out. I ended up breaking two of the locking clips on the coil packs so I just zip tied them back on. Two of the coil packs had the rubber skirt at the top wadded up. That must have happened when the motor was put together.
they didn’t have any coil packs at the auto parts store so I’ll order them and change them next weekend.
i did swap cylinders 2 and 3 coil packs around to see if it pops a CEL this week.
they didn’t have any coil packs at the auto parts store so I’ll order them and change them next weekend.
i did swap cylinders 2 and 3 coil packs around to see if it pops a CEL this week.
Lead Driver
Joined: Dec 2016
Posts: 5,650
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From: GA
I picked up some plugs today and changed them out. I ended up breaking two of the locking clips on the coil packs so I just zip tied them back on. Two of the coil packs had the rubber skirt at the top wadded up. That must have happened when the motor was put together.
they didn’t have any coil packs at the auto parts store so I’ll order them and change them next weekend.
i did swap cylinders 2 and 3 coil packs around to see if it pops a CEL this week.
they didn’t have any coil packs at the auto parts store so I’ll order them and change them next weekend.
i did swap cylinders 2 and 3 coil packs around to see if it pops a CEL this week.
If I’m not mistaken, I believe you can purchase the broken clips.
The coil packs should come with new boots as well so make sure you also get some dielectric grease before installing them on the new spark plugs.
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