2001 Ford Ranger Misses @ 42mph when cold out

46,000 MILES • 6 CYL • 4WD • AUTOMATIC
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BRENDA17
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  • 1 POST
Only when it is cold out, my Ranger misses at around 42 mph. We have tried to find out what the problem is but to no avail. It definately is a mystery. It doesn't miss when it is warm out - only in the winter. What could this be?
Jan 6, 2010 at 11:10 PM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Could be one of the following causing it-Check and test

Oxygen sensor
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
Jan 7, 2010 at 1:14 AM
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