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I bought my 2001 F150 5.4 from my brother. Maybe one out of every 10-15 starts it starts really hard, I usually have to push the gas pedal to get it started. My brother took it to the Ford dealer and they could find nothing wrong when they hooked it up to the diagnostics machine. Does anyone know what this could be from? The guy who previously owned it stored it in winter.........
Now I haven't had the fun of playing with it yet, but...from what I have read in here, there is like a mini coil, one per plug, and they are known for being tempermental and causing just what you are describing. They are called, "COPS". They are kind of expensive, but even worse if you have it done.
Do a search for COPS in this forum and you should find enough info to do it yourself.
I have the exact same problem with mine. It seems more prone to hard starting in cold weather, but it's not a hard, fixed relationship; it has happened in warm weather also.
I have ran fuel injector cleaners through the gas with no improvment. The local Ford dealer had no service bulletins.
My only theory thus far is that there is not enough fuel pressure behind the injectors at start time; therefore, I hold the key in the "on" position for a few seconds. This does seem to help. Or course, the real culprit may be a clogged fuel filter, but fuel filters don't normally affect starting.
I will let you know as soon as I find something out.
If the fuel filter is getting partially plugged it can make the fuel system take longer to "prime" when you try starting the truck. You might want to also try cycling the key from off to run a couple times before cranking it. That helps build fuel pressure.
Racerguy/Steve, thanks for the replies. The fuel filter was replaced and the problem is still there. It seems to happen less during the cold days, yesterday it was around 35 degrees and it started hard for the first time in a few weeks. Does anyone know anything about the throttle positioning sensor? I was told that it could be that.