Re: fuel line adapter
Should run half way decent w/o o2 sensor connected when cold. The o2 sensor is heated and isn't used until the computer system goes into closed loop. Should still run when warm, but will default to what turns out to be a rich mixture. Coolant leak could be water starting to leak out of the weep hole, sign that the water pump is going bad. Thing to look for is water building up/dripping off from under the water pump pulley.
I would be watching the fuel pressure when it's running and checking the computer for key on engine off and continuous memory codes.
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