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2006 Ford Taurus SE, 3.0L Vulcan, AX4N/4F50N transmission
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Discussion Starter · #21 ·
Haven't had a chance to look at live data yet, however, I've put around 200 miles on the car, and I'm noticing a change in my issues, and NOT for the better, unfortunately. When cruising steady at 60-65mph, I've noticed a quick "surge" (noticed tach jumps by about 100rpm, then instantly back down), followed by an immediate pull back that feels like a very slight engine brake. The whole surge/pullback "cycle" is literally over in a second. I can't seem to link anything in particular, other than the fact that it seems to happen more often, and a bit more harsh when the A/C is on, but also happens when the A/C is off. Does anyone have suggestions? I have a bit of free time today, and hopefully tomorrow as well so I can get any data that's needed from Torque Pro & OBDII dongle if necessary.

Edit: Does anyone know if Torque Pro is able to record live data for later viewing?
 

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When the AC compressor engages, that would cause a surge. I feel it in most of my vehicles, but I own a 2005 Taurus SE, 2 '95 4wd F150's, and 1 '92 4wd F150. That surge would be drag that is created when the compressor engages and then the increase in rpms.

Maybe it's less noticeable in newer vehicles, but I haven't found it a problem unless the intermittent surge happens without AC selected or defrost mode.
 

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Discussion Starter · #23 ·
When the AC compressor engages, that would cause a surge. I feel it in most of my vehicles, but I own a 2005 Taurus SE, 2 '95 4wd F150's, and 1 '92 4wd F150. That surge would be drag that is created when the compressor engages and then the increase in rpms.

Maybe it's less noticeable in newer vehicles, but I haven't found it a problem unless the intermittent surge happens without AC selected or defrost mode.
It happens even when the A/C control is in the "OFF" position, just a bit less harshly.
 

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Does it do that randomly or only when you are driving uphill?
Could be that the transmission is switching out of / back into OverDrive because of a lack of torque from the engine. If so, this is still the same problem.
 

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Discussion Starter · #25 ·
Does it do that randomly or only when you are driving uphill?
Could be that the transmission is switching out of / back into OverDrive because of a lack of torque from the engine. If so, this is still the same problem.
It will do the same thing when cruising on level highway, with cruise control set to 60-62 mph. Completely random. if A/C is on, it seems to be a bit more harsh.
 

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Discussion Starter · #26 ·
Is there any live data that I could look at using Torque Pro that may point me in the right direction. I don't really know what the "normal" values are for most of the live data, but I'd be glad to gather as much info as needed to get help with a diagnosis.

Someone above mentioned fuel pressure/clogged fuel filter and that fuel pressure should be around 40 psi. According to the live data I just viewed the fuel pressure remains in the 40 psi range with a fluctuation of 1-2 psi when revving the engine to approx 2500 rpm while running in Park.
 

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Discussion Starter · #28 ·
Just an update, I checked fuel pressure after about a 12 mile drive, and it was around 60 psi while sitting in a parking lot idle.... What is the normal range for fuel pressure? Is 60 psi high?
 

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Discussion Starter · #29 ·

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Just an update, I checked fuel pressure after about a 12 mile drive, and it was around 60 psi while sitting in a parking lot idle.... What is the normal range for fuel pressure? Is 60 psi high?
I do not remember your year but, '02 and later has the power to the pump adjusted to get ~40#. The system does what is needed to get that pressure.
There is a special case where the PCM can adjust the pressue up as in the attached chart, but that is where sitting in traffic in very hot outside temp can cause the system to boost the fuel pressure to handle the very hot inlet air. In this case when the inlet air reached 110F it began to add fuel pressure.
To answer your question YES.
-chart-
 

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Discussion Starter · #31 · (Edited)
I do not remember your year but, '02 and later has the power to the pump adjusted to get ~40#. The system does what is needed to get that pressure.
There is a special case where the PCM can adjust the pressue up as in the attached chart, but that is where sitting in traffic in very hot outside temp can cause the system to boost the fuel pressure to handle the very hot inlet air. In this case when the inlet air reached 110F it began to add fuel pressure.
To answer your question YES.
-chart-
What would be the reason for such fuel pressure readings? Could it be because I was sitting idle in a parking lot in 85 degree weather? Would this have anything to do with the issues I've been having?

Speedometer Gauge Motor vehicle Odometer Automotive design
 

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Haven't had a chance to look at live data yet, however, I've put around 200 miles on the car, and I'm noticing a change in my issues, and NOT for the better, unfortunately. When cruising steady at 60-65mph, I've noticed a quick "surge" (noticed tach jumps by about 100rpm, then instantly back down), followed by an immediate pull back that feels like a very slight engine brake. The whole surge/pullback "cycle" is literally over in a second. I can't seem to link anything in particular, other than the fact that it seems to happen more often, and a bit more harsh when the A/C is on, but also happens when the A/C is off. Does anyone have suggestions? I have a bit of free time today, and hopefully tomorrow as well so I can get any data that's needed from Torque Pro & OBDII dongle if necessary.

Edit: Does anyone know if Torque Pro is able to record live data for later viewing?
I had a 06' 500 with the 3.0 in it and the throttle body used to cause surging like you mention, but mine was while pulling into a parking spot when turning the wheel. Ford replaced three throttle bodies before we figured out removing them and cleaning was all that was needed. I kept the second one to examine (no defects found) and swapped it about every twenty thousand miles when it would start to act up. Once it was removed I would clean it very well, wrap it, box it and it was ready for next time. That continued until I sold the car with 230K on it.
 

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What would be the reason for such fuel pressure readings? Could it be because I was sitting idle in a parking lot in 85 degree weather? Would this have anything to do with the issues I've been having?

View attachment 218973
The capacity to boost fuel pressure when the engine is warm would be a rare event to prevent running lean when it cannot do enough with injector time as in long term fuel trims. I have recorded many trips, many vehicles. This is the only event when this happened. As I remember 101F outside temp, stuck in traffic. This car also always runs positive fuel trims. Not a thing that can or needs to be fixed. However, common that a car system will boost fuel pressure when first started cold for a few minutes. So, high fuel pressure in normal conditions means it is covering up for some other problem.
-chart-
 

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Just an update, I checked fuel pressure after about a 12 mile drive, and it was around 60 psi while sitting in a parking lot idle.... What is the normal range for fuel pressure? Is 60 psi high?
Either way, it it not the fuel pump, and that is good news. A fuel filter or air filter is regular maintenance. Different budget. Did you already check the air filter (this is a matter of minutes)?
 

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Either way, it it not the fuel pump, and that is good news. A fuel filter or air filter is regular maintenance. Different budget. Did you already check the air filter (this is a matter of minutes)?
Should hang around 39-40 but local bouncing +/- couple pounds normal as in the attachment. Note: cold start.
-chart-
 

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Discussion Starter · #36 ·
Either way, it it not the fuel pump, and that is good news. A fuel filter or air filter is regular maintenance. Different budget. Did you already check the air filter (this is a matter of minutes)?
I replaced the Air filter at 146k, I am getting ready to hit 156k.
 

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Discussion Starter · #37 · (Edited)
I was watching the fuel pressure and intake air temp live today while driving. I noticed after driving in the city and the intake air temp started to rise, the pressure was running ~60 - 64 psi. When giving throttle, the fuel pressure would go down into the 50s. Once out on open highway for a couple miles, the pressure dropped back to the 40 psi range and remained there. I also noticed that when the fuel pressure was above normal, it seemed as if the car had less power than usual. I also pulled another Mode 6 report today (attached).

Edit: Note - the sensor name in Torque Pro that I'm watching for the fuel pressure states that it's relative to manifold vacuum. The sensor simply listed as "Fuel Pressure" doesn't work for me for some reason.

Is there another parameter that I could watch that would give some clues as to why this is happening?
Could this in any way be related to the rough idle, and surge/pull back issues that I'm having?
 

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I was watching the fuel pressure and intake air temp live today while driving. I noticed after driving in the city and the intake air temp started to rise, the pressure was running ~60 - 64 psi. When giving throttle, the fuel pressure would go down into the 50s. Once out on open highway for a couple miles, the pressure dropped back to the 40 psi range and remained there. I also noticed that when the fuel pressure was above normal, it seemed as if the car had less power than usual. I also pulled another Mode 6 report today (attached).

Edit: Note - the sensor name in Torque Pro that I'm watching for the fuel pressure states that it's relative to manifold vacuum. The sensor simply listed as "Fuel Pressure" doesn't work for me for some reason.

Is there another parameter that I could watch that would give some clues as to why this is happening?
Could this in any way be related to the rough idle, and surge/pull back issues that I'm having?
Can't read your att. Key to lots of things is long term fuel trims. Under most conditions it should be within +/- 10% If the trims go significant positive when idle relative to under normal load, indicates a vacuum leak. If your fuel trims go high at idle and the PCM can't fix the lean, it can up the pressure.

-chart-
 

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Discussion Starter · #39 ·
I'll try watching live LTFT and report back my findings. Re-attached the Mode 6 report.
 

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I had the same bucking or power gap on my 2006 and another forum member had it on his, TomS. He found that on his it was due to a crushed air filter. You can search for his posts on the subject. I believe my issue was the crank sensor. I found a small metal washer that was magnetically attached to the face of the crank sensor. I had the issue which showed up mostly during rainier weather


 
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