I'm getting right at about 100k miles on my 2002 SCrew 5.4. I'm going to do plugs and COPs soon, and was thinking of doing my injectors while in there. Àny recommendations on which to use? Is this something worth doing? Improve my mpg at all?

Thanks in advance.

 

No its not "worth" it. Injectors last usually the life of the engine. I replaced mine and I think it was a waste of money. No performance gain. Really. But if you really want to there are guys who sell remanufactured sets on E-bay

 

I would not replace the COPs or the injectors unless one went bad. I would do the plugs and the boots only.

 

My understanding is that the COPs can slowly wear out over time without actually "going bad"?

I was thinking of replacing the injectors because they would get gummed up after 100k miles, but maybe I'll run a cleaner through the fuel tank and call it good instead.

 

A couple bottles of Gumout for high mileage engines will make a difference. I think 1 bottle is supposed to treat "up to 20 gallons". 2 in a full tank should be okay.

 

Some of the miss-thinking here is replacing parts not proven to be a problem.
If you have no misfires and no codes, the only part of the ignition system that wears 'erodes' is the plug tips.
The boots can get hard and develop pin holes that may be seen with a scanner looking at the cylinder monitors, only, as high misfire counts but not high enough to set code.
Injectors; run injector cleaner. No codes, no replacement unless proven.
.
Coils, no gradual wear. They either go open on the primary or secondary side winding that would generate a misfire code for that cylinder such that you would know it. The other failure is shorted turns.
This fault shows up as misfires under low throttle in overdrive and sometimes other parts of the drive cycle.
If you have none of these drivability issues, change plugs and boots.
Use no guessing or hear-sey.
You might be better off replacing the OX sensors for fuel mileage concerns but don't expect a quantum leap in any gain. What you would/might get from these is more precision fuel injection 'tracking'.
Good luck.

 

This is probably the only thing you might need to do to your injectors. The pintle caps crack over time. I have no idea what they do.

http://www.ebay.com/itm/Ford-Mercury-Fuel-Injector-Repair-Service-Kit-Seals-Filters-Pintle-Caps-CSKBO18-/190805284230?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AF-150&hash=item2c6ce19586&vxp=mtr

 

I hosed off my motor last summer and came up with a miss. No code but I swapped out for new COP's anyway. Miss went away and my gas mileage and performance improved. 70K miles on the motor.

 

98 F150 5,4L Gas XLT 190k mi
A year ago was getting a good enough misfire to set a code for #2 cyl. so I replaced the #2 coil and plug and all fine. I checked all the coils for open before and all good.
Listened to all the injectors with a long screwdriver to my ear and all seemed to uniformly open. Replaced the fuel filter ( looked moderately crappy dumping inlet side )
Now a year later - intermittent misfiring again but no code. Most of the time runs beautifully on all 8 cyl. I'm gonna replace the remaining 7 coils and plugs and clean the injectors and install a kit with the O-rings /pintails/screens
Questions;
(1) do the original injectors have fuel screens in the top of them to replace ?
(2) Is it possible to have a "lazy" injector that occasionally misfires because it's weak ?