very puzzled, starting problems
 

Hello, new on here. ok, i have 1996 plymouth voyager that will not start. it has the 3.0 in it, we just put the engine in, put in new timing belt and it was lined up perfect, the van did run beautiful for a couple days, put in new water pump, thermostat, coolant temp sensor, spark plugs, wires, cap and rotor, and new intake gaskets. Well when it ran it ran good, heated up fine and everything, then the other day me and the wife went to a couple stores and the van wouldnt heat up at all, and we were out a couple hours and the temp guage stayed on cold and you could even touch the engine it was not hot, the antifreeze wasnt really even moving, so thermostat isnt stuck open, then all the sudden both fans came on while it was cold, so i turned the van off and restarted it and it took a minute or two for it to start, but got it runnin. turned it off and went in store for a bit, came back out and it started right up. go home and park it, get up in morning and again hard to start, turns over for a while but it started, runs fine going to work, then turn it off and try to restart it to check and it wnt start, but i had to go into work, get done after 11 hr shift, it starts right up, get home and turn off and try to restart, wnt start and hasnt since. I checked spark, has plenty of spark, even at plugs, gets fuel, even tried starting fluid and it wnt even sputter, and its getting spark. it will just turn over all day long, plugs arent fouled, all wiring is fine, just puzzled that its getting spark and starting fluid wnt make it run for even a second. Only code im gettin is an o2 sensor code, thats not gonna make it not start. plus its getting spark and fuel.