Ok, so i have an 03 f150 with the 5.4 in it. And ive had the normal problems with the COP's and the misfiring but it doesnt miss or throw codes. Sometimes it will run and drive fine, the accelerator feels soft and easy to push and there is more response to it, kinda has more power and does not slug when going up and hill. But other days, it is very sluggish especially when going up hills, the pedal seems pretty hard to push and you really have to get into the pedal to get it to go and when you do it downshifts really hard. Again it does not miss or stutter it just loses power seems like sometimes. I feel like if i start the truck first thing in the morning and let it warm up, it will do a lot better but if i just take off cold, it does this crap. Anybody know what this could be?? Fuel pump? Weak COP?

 

Really glad you brought this up. If I recall....every truck I have ever owned seemed to have multiple personalities. Some days it's right off the assembly line, others...feeling old. It's more like turns of the key rather than days. My current truck seems to have 3 personalities. None are terrible, but 2 are better, one shines.

Obviously it's timing or electronic, but I wonder what a cure might be...I've thought about this often.

Like dealing with freakin' Sybil sometimes.

 

Scanner
with mode 6 live misfire counts. That is the only way to pinpoint those misfires

 

Sounds like the fuel filter. Are you up on your maintenance?

 

Most scanners can also pinpoint pending misfire even if it hasn't set a CEL yet

 

Yes i have replaced the fuel filter, about 20,000 miles ago though

 

Try that phone app, "Torque Pro". Not sure the Mode 6 will work , but you don't need it. Works great for live misfire data. Last I checked it $4.95