alrighty guys, my good friend who just got back from iraq purchased a 2006 F150 Boss 5.4 and a factory option for these limited production trucks was the intercooled Roushcharger's that came on the Stage 3 roush F150's. when he 1st purchased it it had 53K miles on it, came with full exhaust, an upper pulley and 5 gauges displaying, boost, fuel pressure, air fuel etc... and had a SCT tune but didnt come with the tuner.

about 1 week into owning it, a bad 02 sensor caused the truck to run lean and caused the bottom end to melt 4 pistons. the Ford Dealer he took it to charged him just a tad over $9,000 dollars. yes i couldnt believe it myself. 9 grand just to throw in another stock 5.4L 3v bottom end in the truck and reflash the ECU back to stock. so he lost the tune and the truck wasnt as fast anymore thanks to the stock F150 tune file on it now from ford.

well the truck still ran ok but just wasnt as fast anymore. now, recently the truck is misfiring bad under full throttle (almost sounds similar to a 2-step) and other times runs fine but just isnt quite acting right. we had it scanned and the only thing that came back was 02 sensors.

now my question is, there is no way 1 02 sensor can do this to the truck. could it be a bad COP or spark plug? the only thing i can think of is maybe the plugs arent gapped enough, have too big of a gap, or are possibly foul? or could it be the stock tune? or maybe a combo of both?

i checked and for low boost they should gapped between .030-.035 and for higher boost a colder plug should be used.

is 10psi considered high boost? stock is 5-6.5psi i believe.

any idea of what could be the problem?

i've never worked on a 3v before, just 2v's so this is all news to me. any help would be greatly appreciated!

we just need to get this issue addressed so that way we can fix it and have Justin From VMPTuning have this truck running like a raped ape again!

Thanks!

 

23 views and 0 replies.....

 

32 views now? seriously? c'mon guys say something.....

 

what mods you have?

 

 

Man guarantee you the tune is your problem. With a stock tune on a blown engine the poor bastard is too lean which is probably where your misfire is coming from.