I have a 96 Chevy 1500 2 wheel drive v6. It first started missing a little while I was driving on the freeway. I pulled into a gas station and as I slowed to a stop it started choking and sputtering at idle. I had to get to work so I just drove it a little farther and as long as I kept giving it gas it would run but not perfect. I replaced the fuel filter. It started up and seemed to run fine so as I was pulling out of the parking lot of the auto parts store it died. It would start right back up again but die as soon as I put it in gear. I then checked it with an engine diagnostic computer and it gave me three codes P0719 Brake switch b input circuit low. (It already was giving me this code a week or two before I had any problems). The new codes it gave were P0300 random misfire detected, and P0102 Mass or volume air flow circuit low. I bought some Mass Air Flow Sensor cleaner and cleaned the sensor but it was still running rough. I next replaced the spark plugs. I still wouldn't run well. Some times it will idle fine but when I push the gas it runs rough and sputters. I was told by a mechanic friend I might need to just replace the MAF sensor so I did and it didn't solve anything. Another weird thing it did is, as it was idling I noticed the fuel pump seemed to be making a lot of noise so I hit the bottom of the tank with my hand and the truck died instantly. I started it up again and hit the tank again and it died again. Now it won't start at all. Should I replace the fuel pump even if the computer doesn't give me any kind of code for that and it still gives me the same three codes it did before. Or is there another solution?