My truck has developed a stalling issue that is getting worse. It first did it in November while I was getting to my hunting spot. I pulled up to where I park, and when I shifted from drive to reverse, it quit. Started right back up and never had a problem again that day. A couple days later, I was sitting at a red light, and when it turned green I let off the brake and as soon as I touched the throttle, it quit. It is to the point now that it does it almost every time I try to take off from a stop. It seems to be only when it is hot, because if I let it idle in the driveway up to operating temp, as soon as shift into drive or reverse, it quits. I don't have a fuel pressure tester at home, and it's like 3 outside right now. The thing doesn't quite fit in the garage. My scan tool doesn't show any codes, but mode 6 data shows misfires in cylinders 7 and 8, but not enough to turn on CEL. Oh yeah, it's a 5.4. All the temp sensors appear to working properly looking at live data, as does MAF and IAC. The baro reading seems a little low, but nothing drastic. Has anyone run into this before?

 

check voltages going to your coil packs... How many miles does the truck have?

 

could also be the passive anti theft system......

 

because it fails from low to high rpm's it is extremely unlikley to be from the PATS.........

 

200,000 miles

 

do you know if the spark plugs AND coil packs have been replaced? if not, then it is almost expected for this misfire to occur by now........

 

It had one blow out a few years back, when my Dad owned it. As far as I know the plugs have been done, but the other 7 coils are motorcraft.

 

I'd change out all the coil packs......