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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

  • 52Tele
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1 year 7 months ago #64927 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
And the last one for tonight parked in driveway at 3548 rpm
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1 year 7 months ago #64930 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Okay- you have to let us know for sure. Are your upstream O2 sensors wideband sensors? EQ ratio pids are used with wideband sensors. If unsure- clean off your emissions sticker under hood, it tells you sensors installed on that truck. The one graph you posted earlier showed all narrow band sensors. See graphs on post were Noah Thanked You.

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1 year 7 months ago #64935 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Yes upstream o2 sensors are wide band. The ones I had previously posted were downstream after catalytic converter they are narrow band

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1 year 7 months ago #64936 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Okay- changes how we look at this now. On your scanner can you find a voltage pid for each of the upstream sensors. I think Ford is around 3 volts, if you are sitting at idle and the truck is at stoich.

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1 year 7 months ago #64937 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Yes but I believe it shows as milliamps I can double check that in a moment. I may switch over to my otofix scanner.

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1 year 7 months ago #64953 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
I'll be posting a few screen shots in a moment. So I noticed there are times that the upstream sensors current data comes through as milliamps and other times it's switches to what seems to be voltage. Does anyone know if that is supposed to happen?

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1 year 7 months ago #64954 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Beginning and after wide open throttle 
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1 year 7 months ago #64955 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
I have some more if anyone is interested or thinks it's needed for more information.

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1 year 7 months ago #64956 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Sorry this is the after
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1 year 7 months ago #64961 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Your after screen shots- jpeg 319_022136 of negative 883 microamps. I have never seen that before with a wide band sensor.Do you by chance have another scan tool or can borrow one?

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1 year 7 months ago #64962 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
I have the Otofix D1 lite and a topscan. If I remember correctly it's shows the same way on both. I can check with the TopDon topscan when I get off work. I thought that was weird as well why it would only report as voltage in a certain range. I saw a video on the scanner danner page I might re-test tonight as he mentions using global obd2 data instead.

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1 year 7 months ago #64963 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
Also if you look at the before photo it shows both sensors as uA before I get on the throttle.

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1 year 7 months ago #64966 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
So for some reason the topscan is measuring as milliampere and the Otofix is measuring as microampere.
I noticed a moment ago.
My commanded duty cycle is
bank 1 67.84%
bank 2 61.96 %
Scan tool says heater is on for both banks and also that the control is on.
It also says there is no fault for heater control. 
But the pid for heater current monitor is reading 0 mA.
Does this mean the heating circuit isn't working and that's why it's showing such small measurements and only when I had it in the specific range I mentioned earlier was it hot enough to report properly?

 

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1 year 7 months ago #64967 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
An open heater circuit would flag a code on a wide band sensor. Your "after'' jpeg 319_022353 lambda readings and negative current flow suggest sensors are working at least on fuel enrichment. did the truck have the very rich negative fuel trims at idle before you replaced those upstream sensors?

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1 year 7 months ago #64968 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Please do me a favour. Next time you take the truck for a drive graph the following: engine rpm, mass air flow gms/sec and a voltage pid if provided for the maf sensor. try idle, normal cruise speed and a bit of heavy throttle. Thanks.

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1 year 7 months ago #64973 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
I replaced those upstream sensors in may 2023. That's back when everything sorta began and it's just been a slow ongoing process of me checking things and trying to get everything figured out. I cant remember at the moment what they were then but might still have some scanner data I'll check.

This vehicle uses a MAP sensor like previously mentioned when I asked about the difference in intake air temperature readings. So no mass air flow on this truck.

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1 year 7 months ago - 1 year 7 months ago #64974 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Does this truck have vvt or is there an egr valve on it?
Last edit: 1 year 7 months ago by bills4065. Reason: Change the question.

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1 year 7 months ago #64979 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
VVT/VCT. That's one of the other things I had mentioned earlier about being concerned about.

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1 year 7 months ago #64981 by bills4065
Replied by bills4065 on topic F150 No code intermittent misfire issues
Right, you did say that. Sorry - the map sensor pid, what is it reading at idle? Being Ford probably a Hertz signal.

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1 year 7 months ago #64983 by 52Tele
Replied by 52Tele on topic F150 No code intermittent misfire issues
At idle currently intake air temp is 111.2 and voltage is 1.63

Manifold absolute pressure is 4.21 psi
And voltage is 1.34

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