My 2004 ford truck is currenlty running very very poorly. It recently began to exhibit rough driving conditions. I discovered under the fuse relay box in the engine compartment that there are 2 relays are missing. 302 a larger relay and 203 a smaller relay. I don't know what these control so I don't know if it matters. I also have someone tried to connect a code reader and said that it wont read anything. The computer isn't on or communicating. Said that there is a ground issue common in fords. It is a 2004 Ford Heritage v6 however it takes parts as if it were a 2003 and the build date is 9/2003. It is a canadian build.

 

There is also quite a bit of buildup on the negative battery cable could this be my ground problem causing the poor running.

 

does the cigarette lighter work on your truck? not the power port, but the light port itself
I know on the 97's the fuse for the lighter is also for power to the obd port.
and clean the battery terminals good.