car wont start..again

[dipset891]

i got 97ex i just tuned it up after it had died on me while i was driving so now i drove it for bout 15 then parked and out of nowhere it died and it wont start again so the same s**t that was before the tune up
about a month ago i had to put a new aftermarket 02 oxygen sensor to pass the state inspection . i was wondering if this could cheapo sensor be the cause of the car not starting .
btw the check engine light hasnt come up
appreciate any help

 

[turbowhat_n_dat]

1 does it crank???
2 do you have spark???
3 is your fuel pump working???
4 is there an engine/tranny ground that is loose???
5 is there a loose connection at any electrical components???
6 there are so many things!!!!!!!

Need more details.