Ford Repair: 1994 Ford Ranger, mass air flow sensor, mass air flow

Question
Hi, I have a 1994 Ford Ranger with a 2.3 4 cyl. that does'nt want to rev. up. I've replaced the fuel filter, spark plugs, and checked for any leaks in the fuel and vacuum lines. Then I replaced the mass air flow sensor. I did this after I discovered that the engine would idle either with the mass air flow unplugged or the air hose off of the throttle body. After all this my buddy brought over a code reader for ford and the codes were as follows. 157-MAF sensor fault, low voltage   543- fuel pump secondary circuit/ fault   556- fuel pump relay primary circuit/fault. Now it wont start at all. We read the codes before I put on the MAF sensor and the 543/556 did not appear. The truck had been sitting unused for a year or so before  I got it. Sorry about being long winded. Any ideas?

Answer
sounds like fuel delivery problem-old gas can ruing injectors and or fuel pump-test fuel pressure first then you may have to test/clean injectors if fuel pressure is weak when you remove pump for replacement be sure and check tank especially if screen on pump is clogged with syrupy residue from old gas.