2003 6.0 starts and idles but can't drive

[cminzey]

I have a 03 f250 6.0 the truck idles good and drives some what ok up 25 mph but then stalls and falls on it's face then it stalls after 25 mph then hard to restart fuel filters are new and filter underneath drained and cleaned, oil is at full mark, fuel is fresh, new alternator the old was putting out under13 volts can anyone help

[EMVT]

Try disconnecting your Cat. See how it runs then.

Also, check your fuel pressure from the low pressure pump, should be more then 45psi.

[cminzey]

would either of these cause this not to be driveable I know the pump could be an issue but didn't know about the cat , on the low side pressure where do I ck it at fords are new to me

[EMVT]

the cat is simple enough to check, just unbolt it. I have a homeade gauge that adapts to one of the fittings off of the filter/pump.