My 2015 Explorer 3.7L with 135,000 miles shows a misfire code on cylinders 3 and 4. Nothing you can feel or notice. Takes 200 or 300 miles for the CEL to come on. Makes simple diagnosing difficult as doing the coil swap would take a long time to show results. Scan tool shows no misfire events as I monitor it and shows only 50 to 80 misfires on those cylinders since the CEL was last reset. Any other test to make without a scope that might show a cause? Pulled one front plug and it looked just fine, like it may have been changed at the last 120k service. Going to change all of them anyway and ordered 3 new Motorcraft coils. Will put the new coils in the back as they are much harder to get to. Anything else I should do while the intake is off?
Misfire codes taking over 200 miles to set.
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check the fuel filter and air filter also check grounds and chewn on wires
X2....I see it quite often on 3.5L Ecoboost engines.
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What is it with Ford and spark plugs/ignition systems? The number of problems with Fords and their spark plugs/ignition systems the last 20 years is laughable.
As far as "taking 200 miles" to set a code/etc., does it really take that long or does it take 4-7 drive cycles? I recently had a check engine light with Trac Off display come on with my 2015 Lexus RX350. I looked up what this might possibly be, one was the common loose fuel cap. Before the next drive cycle, I loosened it and tightened it. Made sure it was tight. Drove another 20 miles. Lights still on. Great, must be something else.
More research says could be a coil, loose wire, O2 sensor or Cat. Awesome. One report was the lights went away after re-fueling.
Another drive cycle (about the same as the last, ~15-18 miles), lights still on. My next stop was re--fueling. Made sure the cap was tight. Crank and get back on the interstate, BAM!!! I notice no lights. But wait, there's more.
About a week prior, I pulled the #4 plug to look. I'm planning on replacing the plugs and rear three coils. So when I re-fueled, I removed the coil wire and put it back, making sure to push hard.
So I really don't know if it was the fuel cap the first time (Highly suspected) or the coil wire or the magic re-fuel. But if it was the fuel cap originally, it took quite a while to re-set, 2 drive cycles and a re-start. That could have easily been "200 miles" or more.
As far as "taking 200 miles" to set a code/etc., does it really take that long or does it take 4-7 drive cycles? I recently had a check engine light with Trac Off display come on with my 2015 Lexus RX350. I looked up what this might possibly be, one was the common loose fuel cap. Before the next drive cycle, I loosened it and tightened it. Made sure it was tight. Drove another 20 miles. Lights still on. Great, must be something else.
More research says could be a coil, loose wire, O2 sensor or Cat. Awesome. One report was the lights went away after re-fueling.
Another drive cycle (about the same as the last, ~15-18 miles), lights still on. My next stop was re--fueling. Made sure the cap was tight. Crank and get back on the interstate, BAM!!! I notice no lights. But wait, there's more.
About a week prior, I pulled the #4 plug to look. I'm planning on replacing the plugs and rear three coils. So when I re-fueled, I removed the coil wire and put it back, making sure to push hard.
So I really don't know if it was the fuel cap the first time (Highly suspected) or the coil wire or the magic re-fuel. But if it was the fuel cap originally, it took quite a while to re-set, 2 drive cycles and a re-start. That could have easily been "200 miles" or more.
I replaced the plugs (which looked fairly new) and the rear coils. The coils were no-name probably Chinese so I'm pretty sure that was the problem. Runs fine so far.
I am guessing it's the catalytic converter.
You came up with that after consulting your crystal ball?
New gasket, I'm thinking vacuum leak could also be an issue and being 3.7 should be a v6 but separate banks, I'd look for common area to 3 and 4 such as the gasket or vacuum port, pcv valve, ect.
Bad fuel injectors can also cause misfires.
Been code-free since I replaced the plugs and coils.
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