1989 Dodge Caravan starting problem

I have a 1989 Doge Caravan 2.5L enging non turbo VinK. Recently, my minivan began to have starting problem. When I try to turn on the ignition the car won't start. I spray starting fluid in the throtle body, then I tap the botton of the fuel tank. This action start the engine. This happens sometimes. I suspect that I may be having problems with the fuel pump. I checked the the codes that is flashed from the EMC and I got code 12, 11, 15, 22, 55, 55. I changed the o- ring on the distributor base because the old one was cracked and oil was zipping out from distributor. I did this change after I started to have problems starting the car. I don't think this is ralated to the starting problem. I believe that EMC flashed code 11 because I try to start the car wthout connecting the pick up coil to the distributor. I forgot to do this before starting the car after working on the distributor. My mother purchased the minivan 10 years ago from a dealer as a used minivan. Since it was in my mother's possesion, the fuel pump has never been serviced. I also suspect that it could be the ASD relay. I will appreciate any honest opinion as to what could be the cause of this problem. Thanks