1994 subaru impreza chokes down and just about runs. also neutral indicator for door ajar doesn't work. give support to!?

My husband thought it was the fuel pump and changed it, but it still will not bear the gas. It has him so puzzled. A couple months ago the check engine street lamp came on and he thought it be the transmission so he changed the filter and it help, but it is so sluggish it won't hardly progress up a hill, and explicitly why he thought it may be the fuel pump. Help! Thanks