1998 Chevy Metro wont start

Hey Guys,
Here's my problem, and it is a brain teaser for me. I have a 1998 chevy metro 1.3 liter, fuel injected, automatic, with 120,000, my problem is it will not start, not cold or hot, the only way I can get it to start is with a shot of starting fluid, then it runs smooth as can be, I bought a part car same make and model, that runs at all times with no problem, I have replaced all parts, fuel pump, injectors, all fuses, the gas tank, relays, and the computer, and still no good. Can you tell me what is going on? Please ! This car ran great until I took it in to get a exhaust pipe welded on the my car, now its gone to hell. What is the deal any clues? :Idea: Please get back with me, I appericate all your help and knowledge.
Jeff :evil: :x ?
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