Update: Checked fuel pressure. At idle 30psi on both pumps. With the FPR unplugged 40psi. When I rev it a bit pressure goes up to about 34psi both pumps. What story does this tell?

 

If you are getting a code 157 I believe you have unmeasured air getting into the engine that the MAF sensor is not measuring. When it comes to vacuum leaks , "never say never" ! I would suggest you check the throttle body for a worn shaft or shaft openings.
Those kind of vacuum leaks sneak past us when we aren't looking for them.

 

I just went back over it again checking for vacuum leaks yesterday and did not see any. I checked around the throttle body really good and also all the lines and the resevoirs. I'm stumped and don't know what else to do. I've been told that the fuel volume isn't enough but I have 2 fuel pumps and it does the same with both of them.

 

Anybody have anything new for this problem? I have since put in a new fuel pump in the rear and blocked off the front pump, don't use it anyway, also MAF and o2 have been replaced. I'm thinking this is an electrical issue but just haven't found anything on it yet.

 

Well this gets curiouser and curiouser. The code 157 means the wire (if memory serves correctly its tan/lt blue or lt blue/red) did not supply the right voltage to the pcm. The really interesting thing is, if this truck has a Mass airflow sensor (not the MAP sensor), then it's a california only child, as they were the only states that used the MAF system in this body style in those years. This generation has a bunch of tsb's about the MAF connector that went to it, as they used tin and not gold plated terminals. The first thing to do is replace it. Ford has a connector pigtail for it that you cut out the orignal and replace it (I think the part number was F43Z-14A411-A, but could be mistaken,as there were alot of drugs between then and now). After that, if the code resets, check the input to the pcm.
The code 173 means the O2 sensor was stuck rich for longer then 15 seconds when the pcm knew the fuel system was in closed loop, and drove the system lean to try to get a proper respose, but couldn't. These has a lot of problems with battery acid eating up the o2 wiring (the o2 wiring went down to the o2 in the same loom as the positive battery cable; it would eat up the cable and jump ship to the o2 wiring and short it out; very common problem). However, with the code 157 in there, it is conceivable that it was caused by the MAF. There was a connector near the battery trey you can backprobe, but fix the maf first.