so over the past five year that I have had the truck which I got with the supercharger. I have had this problem over the last three years. It all started with the common misfire/hesitation/vibration problem. I have probably spent over 20 thousand so far on parts and labor plus my own man hour as well tryin to get to the bottom of this problem. So far I have replaced the transmission, only 15,000km on it, re tuned twice with at reflash back to stock to pro tune it. High flow cats, magnflow exhaust, complete pro charger system, new spark plugs for the 3rd time this year, brand new cop’s, new air filter, fuel filter, replaced fuel pump on start of 2016, pretty much changed out every sensor you can think of except crank position sensor, here is what has also been done while it been in the shop this past week changed the coils to oem ones, no difference at all

*confirmed voltage to the coils, they are at alternator voltage


*took plugs out and they are look new, slightly hot, but ok so didnt change them, i didnt see a reason for it.

*compression & leakdown test, passed with flying colors.


*confirmed the tune, it is commanding the correct amount of spark as programmed (not pulling any timing) and air/fuel ratio is exactly where it should be.


*confirmed the fuel pressure, it is fine and fuel pump duty cycle is low (good)

*I have confirmed the cam timing error to be correct, but i do see some light fluctations at part throttle left to right banks

*confirmed the truck isnt hitting a speed induced or rpm induced limiter or temp based limiter in the pcm

*checked intake air temps to confirm fueling, also the cats have been checked as well and they are clear. Me and my mechanic are at a point where we are looking for any and all suggestions and at this point we are looking at possibly a ne pcm and retune but Their is no guarantee that that is it either.!so after three long years and tons of time trying to find answer to what is the problem on all the forms I am hoping I can get some fresh ideas to pass on to him soon. This problem is so intermittent that we are both stumped and everything thing says it’s running fine but he has even had it do the it for him. I hope someone out there can help and thank you

 

What brand and part number spark plugs are you using? If they looked hot, I'd try 1 heat range colder.

 

Can’t remember exactly but I have all sorts of different plugs over the last year. I think some of them have been the Ford rracing once I will find out the exact ones and get back to you. And see what he has been putting in.

 

I have heard that the best plug for a supercharged 5.4 3 valve is the Autolite HT0. It's 1 range colder than stock.

 

Ya I think he said he had those ones in their and the Ford race ones where in there before that getting ore infor on the situation in the afternoon about the truck as well but as far as I know from the last conversation I had with him we are at a loss. Other then chancgeing out the pcm and returning it I’ll mention those plugs to him again and make sure we haven’t tried that thanks

 

Yup useing the higher heat range ones

 

With FI, seems to me you need lower, not higher.