1stTruckGuy

So I am having this misfire seemingly all the time, but it does not set a code. I have replaced all 8 spark plugs last weekend with sp515s which made no difference. Next I replaced fuel and air filters. I had previously replaced both vct solenoids as well, no change. I broke down and ordered new cops which I will be installing in the morning to try and fix this.

What I find strange is that when looking at mode 6 data I don't see any misfires, all cylinders show as passed for the tests. Even when holding the throttle at 1200 rpm when you feel the truck shake from the misfire everything shows fine on the scanner. Is there something else I should be looking at? If the cops don't do anything for me, does that just leave fuel injectors?

05 lariat screw, 107k miles.

techrep

iTrader: (1)

If the COP's don't fix it...I would check the condition of your FPDM...if you have not already.

1stTruckGuy

I have an fpdm on order as well, it will be in next week.

techrep

iTrader: (1)

one of the 2 should fix your un-detected mis-fire...I think a mis-fire needs to be more sever to set a CEL and store a code...very common ...people report mis-fire's with no codes all the time. good luck and let us know the results of your effort.

Synyster06Gates

This is EXACTLY my issue! To the T. Same thing on mode 6. Doesn't show any issues. I've been advised to look into the injectors. I'm new to the F150 world so this may be incorrect, but I believe there was a recall on the injectors as well as (at least MY truck does have it- I called a dealer) an extended warranty to 11 years or 120k miles on the injectors.

1stTruckGuy

Well I'll be putting the coils in tomorrow and new fpdm next week. If problem is still there it has to be injectors. If I don't have a code thrown though, I don't think ford will do anything but charge a diagnostic fee.

techrep

iTrader: (1)

I think if it were the injectors causing the mis-fire you would get a lean bank 1 or 2 PO171 and PO174

1stTruckGuy

Well I got antsy and decided to do the COPS tonight. All 8 installed in about 30 minutes. I put dialectric grease in the boots of all of them before installing. Well sad to say it made NO difference at all. Still misses at 1200 rpm like clockwork, and you can feel it miss at idle. This means my original COPS were fine, so now I have 8 good spares, I'll keep one in the truck just in case.

my FDPM will be here in a few days, if that doesn't solve the problem I'm gonna have to fork out a hundred bucks to have ford look at it. I double checked my vacuum hoses too, all look in good condition. No check engine lights or stored codes. Do bad fuel injectors always throw a code, or is it just catastrophic failure all at once and blows/hydrolocks the motor? Any idea what Ford will get me for to install all 8 injectors? I'm pretty sure I could do it myself in the garage if I can find a good price for the injectors and I know for certain that one or more are bad. If I'm gonna replace one bad one, I'm gonna replace all of them for that warm fuzzy feeling.

I took a short video tonight after doing the COPS and changing oil over to 5w30 full synthetic.


After all of the preventative maintenance work I've done (spark plugs, fuel filter, air filter, VCT solenoids, COPS, cleaned throttle body and MAF), it still runs and sounds just like it did when I bought it 1k miles ago. I feel like I just threw all that money away at this point. Only thing left in my mind is fuel injectors, exhaust manifold gasket, and cam phasers. These are, of course, the most costly of repair items right behind a transmission rebuild (crossing my fingers I don't have that to look forward to anytime soon).

jamesaltmann723

I had a similar problem, random miss but this was while accelerating lightly in overdrive at about 40 mph and low rpm. I did the fpdm, changed to 5w-30, and all the other maintenance things but no difference. Just before I changed my cops and plugs I tried custom tunes from PHP and it cured it completely and it runs better than ever now! I only have exhaust and the gotts intake mod but I told PHP about my mods and they wrote a tune for it and now it's perfect so you may want to look into custom tunes before spending more money (60$ versus a 1000$ tranny rebuild!)

1stTruckGuy

My truck is fully stock, exhaust, air intake, etc. I love the truck, but a guy offered me 15500 for it, which is what I paid for it out the door. I've since put almost 500 bucks in maintenance into it, thinking of taking a hit and letting it go. At this point I can't afford a cam phaser job if thats what its going to take to fix the noise and idle. Its gotten to the point that when I pull up to another f150 at a stop light I turn off my radio and roll down the window to see if their truck sounds like mine. Of all the ones I've seen, I've only encountered one that made all sorts of racket, I could hear it across the parking lot and mine does not sound like that. There is a good liklyhood that I have an exhaust leak since I have no noise at the front of the motor, even with mechanics stethescope on the timing cover.

I just want to hear that the noise is normal and its not gonna explode :o) I'll drive it for two years and then upgrade vehicles like I usually do and that will be that.