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Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

F150 No code intermittent misfire issues

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1 year 7 months ago #64873 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Your total fuel trim is the sum of the long term and short term for in your situation each bank. Bank 1 is 17.18 and Bank 2 is 39.84- there is definitely something not right. As for why such a difference between the 2 banks-i do not have an answer. Maybe some others can answer that question. I would still check fuel pump pressure next. Has the truck set any lean codes?

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1 year 7 months ago - 1 year 7 months ago #64877 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
No haven't had any codes but I also haven't held it for a long time at 3500 rpm for those fuel trims to be that bad for a long amount of time. I noticed it seemed like they started getting worse around 3000. I've done fuel pressure test on vehicles with Schrader valves on the fuel rail but never on one without. I'm assuming there is some kind of adapter?
Last edit: 1 year 7 months ago by 52Tele.

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1 year 7 months ago #64878 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
F150- should be schraeder valve on fuel rail.

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1 year 7 months ago #64885 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
I don't remember seeing one when I swapped injector 6 to the other bank but I'll double check when I get off work.

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1 year 7 months ago #64896 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Just to follow up there is not a Schrader valve on the stock fuel rail.
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1 year 7 months ago - 1 year 7 months ago #64897 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Is there a way to share images on here? I was going to share a screenshot of the crazy fuel trims I had a little bit ago.
​​​​
Last edit: 1 year 7 months ago by Noah.

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1 year 7 months ago #64898 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Trims worst at 3000 rpm plus, still looking like fuel delivery / volume issue. Would have to tee in with no Schrader. Not sure on how to for images- some one who knows will probably chime in.

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1 year 7 months ago #64900 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
OK thanks. Today while at lunch in the truck in park with ac on I had really rich fuel trims anywhere from -10 to -28.79.

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1 year 7 months ago #64906 by Noah
Replied by Noah on topic F150 No code intermittent misfire issues
Click the "Add Files" under the heading Attatchments below the text entry field. This will prompt you to open your gallery and chose an image from the list of supported formats, then click "Insert"
 
"Ground cannot be checked with a 10mm socket"
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1 year 7 months ago #64907 by Noah
Replied by Noah on topic F150 No code intermittent misfire issues

Is there a way to share images on here? I was going to share a screenshot of the crazy fuel trims I had a little bit ago.
When you do post the screenshot of the fuel trims, please be sure to include long term and short term fuel trim for both banks along with RPM and fuel system status (open loop/closed loop). Excluding any of those PIDs will make it very difficult to gauge total trim.​​​​
"Ground cannot be checked with a 10mm socket"

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1 year 7 months ago #64910 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Sorry the rpm wasn't on there but these were at idle. Twice after pulling up and stopping at a red light. And the one with short term trims of  -21.1 bank 1 and -19.5 bank 2 that screenshot was at lunch parked with ac on. Rpms were anywhere from 530-600
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1 year 7 months ago #64913 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Here is where you are at: at idle both stft taking fuel away,- both downstream O2 sensors at .950 volts do suggest rich. What were the upstream O2 sensors reading? At 3469 rpm both banks are running lean. Noah's suggestion of pids to monitor great idea. Your idle readings were taken in closed loop. Has truck had an oil change lately?

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1 year 7 months ago #64916 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Let me check how it's doing today and get back on here with findings I know it sounds weird but it sometimes fluctuates pretty dramatically on different days

On the oil change I have went a little over when I normally would because i was having the VCT actuator concerns so I wanted to see if a longer oil change interval made it any worse. I haven't really seen that and it seems like oil pressure has been good. I  was planning on changing the oil probably sometime this week though. 

Another question I have is what symptoms would a intermittent sticking purge valve have?

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1 year 7 months ago #64917 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Myself - before I would change anything else, I would do a wide open throttle run and graph my upstream O2 sensors only. Ensure they both go full rich at wide open throttle. Let us know how this goes.

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1 year 7 months ago #64921 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
So drive with the throttle wide open? How long of a test does it need to be?

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1 year 7 months ago #64922 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
I'm going to post a few scanner images from a drive a little bit earlier as well.
Also the map sensor on the trucks reads the manifold pressure as well as intake air temperature. Tonight I noticed intake air temp up to 109.4 at idle and 98.6 just normal driving with throttle partly open. The outside ambient temp at the same time as those readings was 57 degrees Fahrenheit. Is a gap that big normal between ambient and intake air temp?

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1 year 7 months ago #64923 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
This was while doing a deceleration coast. 
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1 year 7 months ago #64924 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
This was a random idle capture of rpm and upstream data. 
 
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1 year 7 months ago #64925 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Another random capture at 1733 rpm while driving. 
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1 year 7 months ago #64926 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
This is right after going back into closed loop from a deceleration. To me this doesn't seem normal but again trying to learn more if I'm wrong. The rpms were 931. 
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