2001 Ford Taurus SE Hesitation and Missing Problem

2 scanners have shown no trouble code and that is why parts have been thrown at the problem. Three mechanics (two certified) have tried to diagnose the problem so far based upon what their scanners read. Their
scanners say there is no problem but the driver says different.
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tajones wrote:

Well now, you didn't say that before. Could be electrical, but if code reader didn't show anything, it's most likely mechanical. It could be the fuel pump, fuel filter, or fuel pickup sock (filter) in tank. If all else fails, drop the tank & clean it; I had to do that once, to solve the same type of problem.
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At this point, I would verify that the fuel pressure is good WHILE THE CONCERN IS HAPPENING. If this proves good, then we get into diagnosis by symptom and your tech will need a scan tool with flight recorder capabilities. This method works but the tech needs to be sharp....
I would start with monitoring short and long term fuel trims, upstream and downstream O2s, TPS and MAF... what I saw here would indicate which PIDs I might need to add or ignore during diagnosis.
Other considerations... were any changes made just before the symptoms appeared.... add-on accessories? Repairs? Gas purchase? Is the speedometer reading steady or is it jumping all over? Has the charging system been tested for excessive alternator "ripple"?

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Have they replaced or updated the drivers?
Bill
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Try this... warm the car up. pull over and shut off, disconnect the MAF harness connector. Drive car to see if the symptom changes for better or worse: Better = the MAF is dirty or out of calibration Worse = There is another sensor at fault, possibly BAP
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I had similar bug in my 88 5.0 'Stang. It was coolant sensor. No trouble code. The "brick" thought engine was cold and kept feeding more fuel.
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