Its a ford!
Thread Starter
Joined: Oct 2009
Posts: 4,156
From: Coal City,Il
Its a ford!
My kid's Ranger to be exact. I assume this is more of a general problem rather than specific to the Ranger.
Anyway, were getting multiple/random misfires all throughout the RPM range. It happens intermittently but never before the truck is fully up to temp. So itll run perfect until its up to temp, then random misses start. Theyll clear up for a few minutes then come back.
The main thing here is as soon as the missing starts, BOTH upstream o2 sensors basically flatline. It flickers between .0-.1, both of them flat line together and come back to operation together.
When its running good, the o2 sensors give good readings .3-.7 commanded from the PCM which I have verified with a multimeter. I have also verified the flatlines with a meter as well. Weve also bench tested the o2s.
Any help is appreciated.
Anyway, were getting multiple/random misfires all throughout the RPM range. It happens intermittently but never before the truck is fully up to temp. So itll run perfect until its up to temp, then random misses start. Theyll clear up for a few minutes then come back.
The main thing here is as soon as the missing starts, BOTH upstream o2 sensors basically flatline. It flickers between .0-.1, both of them flat line together and come back to operation together.
When its running good, the o2 sensors give good readings .3-.7 commanded from the PCM which I have verified with a multimeter. I have also verified the flatlines with a meter as well. Weve also bench tested the o2s.
Any help is appreciated.
Joined: Apr 2010
Posts: 12,590
From: Mentor, Ohio
That is weird! What year Ranger? v6?
My ex-wfie had an 01 Mustang and it had a problem where it ran rough because of a sensor that commands the variable rate fuel pump. I forget what Ford called it. I recall there was a simple test with a multimeter. ANd ti was very clear the problem was a sensor. Smooth idle and then out of no where like a switch was flipped a rough idle.
My ex-wfie had an 01 Mustang and it had a problem where it ran rough because of a sensor that commands the variable rate fuel pump. I forget what Ford called it. I recall there was a simple test with a multimeter. ANd ti was very clear the problem was a sensor. Smooth idle and then out of no where like a switch was flipped a rough idle.
Thread Starter
Joined: Oct 2009
Posts: 4,156
From: Coal City,Il
That is weird! What year Ranger? v6?
My ex-wfie had an 01 Mustang and it had a problem where it ran rough because of a sensor that commands the variable rate fuel pump. I forget what Ford called it. I recall there was a simple test with a multimeter. ANd ti was very clear the problem was a sensor. Smooth idle and then out of no where like a switch was flipped a rough idle.
My ex-wfie had an 01 Mustang and it had a problem where it ran rough because of a sensor that commands the variable rate fuel pump. I forget what Ford called it. I recall there was a simple test with a multimeter. ANd ti was very clear the problem was a sensor. Smooth idle and then out of no where like a switch was flipped a rough idle.
I guess that info might be useful, thats me in a hurry. Its an 05 with the 3.0.
Thats interesting because my research keeps pointing me to a FPR. Sounds strange but as you look into it more, you realize the FPR is supposedly built into the fuel pump and the test for that is putting a multimeter on a sensor on the tank.
Well I have a couple clues then. Time to untangle some wires!
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