Problem with cold start Floods out, won't start
 

Man this is a good one.. Im gonna throw out ideas as I cant see your car.

O2s will code out when soaked in fuel. The primary "upstream" gives feedback to the ECM. The down stream simple sends signal for emissions. So save the old o2.

Are you burning the primary o2 wires? Did you cut or splice this assembly? Are you burning sensor wires in general? The run after the sensor swap is a clue but something then failed so ground or wire strain or burn?

Did the dealer give you a print out of the data? I HATE to not give you an idea of where to go but honestly you need someone with the ability to read ecm data. For 75 bucks the dear should have given you that. A snap on or equivalent tool that can give you "run" voltage and "engine on" voltage. The system needs a way to tell the parts what ambient air and temp is. If these voltages are out of parameter they wont work. She may "limp" for you but not run right.

Excessive fuel in a system that works well leads me to temp sensor ( which you changed) and then TPS ( where the throttle blades are opened too ). I would check voltage there and see where you are. Clogged converters do this too.

Have you been running withcheck engine light for a while? Say 30 plus days and this happened?

The OBD2 in your car will run two system checks. An instant MIL or one that codes after 100 miles or 2 hours.. Or a combination of the two. These lights are for the consumer. You can read much more in the ecm. If you go back to the dealer ask for the senior tech. Ask him to read all the cached data and check all your sensor readings.

The check engine light never came on.

check engine light
 

there is no check engine light, the only code that ever came back was checked at advanced and that showed the o2 sensor. That has been replaced. It didn't throw anycodes at the dealership and they said they didn't have a print out. They were very unhelpful and wanted to charge over $600.00 for checking it out even though the agreed price was $89 for a diagnostic check. they pulled the timing cover off and the manifold and said the spark plugs were bad ( just replaced) and the timing was off. Told them we were only paying the 89 and we towed the car home. Replaced the spark plugs again this time with champion plugs. The ones I just replaced were already gassed out. Checked the timing and as we thought it was in time. Any Thoughts?

Thanks PK1 for your input, I'm forwarding on to the Neighbor mechanic who is helping with this.

If it started all of a sudden it would be helpful if you can remember any recent work leading up to the issue. Pull a plug and ground it against the block (still hooked to the plug wire of course). Have a buddy turn it over. Got spark? Let us know. By the way, diagnostic work is the best and cheapest way to find and repair the problem, throwing parts at it is the most expensive.

I have a funny idea that the air intake is getting plugged intermittently. Not likely but easy enought to check. You would be surprised at how quickly a mouse can make a nest in the oddest places.

Other thing is a cold wire syndrome. That means that cold the wire withdraws far enough to cause problems but works fine when warm. Look for places around the battery that are bulged out. If you slice them open and its all white powder on the wiring harness you found it. If your battery is not under the hood it can still happen in places under the hood anyways.

Cam position sensor ? jumped timing chain ?