Truck Repair: 99 f250 superduty 4x4 5.4 auto w/ac, egr valve, fuel pressure

Question
hi, rusty. help me out here... truck runs like it's got several misfires at once... once had codes for egr and #5 misfire... have replaced egr, fuel filter, plugs, coils... have double-checked all vac lines, fuel pressure, all grounds... replaced computer... no change... once in a while, truck runs fine, then instantly goes into this fit and won't come out of it... i have no codes and can't even set one when i unplug a coil when the truck's running! what am i missing? what about crank/cam sensors? or dpfe? shouldn't i get a code? would pull out hair if i had any... i'd appreciate anything you can think of... thanks, roger

Answer
I just ran into this same problem on a dodge V8. the catalytic converter was plugged up causing the egr valve codes when the exhaust system backed up. you may also find the fuel system flooding out and causing your fowling cylinders. see if you can check the converter or just see if the air comming out the tail pipe seems weak.

this problem has frustrated many techs.  good luck and let me know how you did.     rusty