Dodge Repair: 98 Stratus Wont Start, fuel pump relay, many different things

Question
Hi Kevin,

Having a problem with a 98 Stratus with the 2.5l V6 engine.  I just finished installing a used engine after the original one suffered a major failure.  After getting everything connected, I was able to start the car and run it briefly several times to do leak checks, check for fault codes, etc.
The last time I started the engine, I let it run for longer than the previous starts to get things up to temperature and top off the cooling system.  While running, the engine started running rough, then quit.  Since then I've been unable to get it to start again (cranks fine, just won't fire).  Double checked electrical connections and can't find anything.  No engine applicable codes, though I am getting one for the TCM, P0700, that I haven't been able to troubleshoot yet, but I've read that it could be a ground problem (did not have the code prior to the engine swap).
I can hear the fuel pump coming on when I turn on the key, and I checked all related fuses in the engine bay.  I didn't try troubleshooting the fuel pump relay, as I figure I wouldn't hear it turning on if the relay was bad.

Changing this engine was a real chore and I'm really frustrated now.

Any ideas on what to check would be appreciated.

Thanks in advance,

Jim

Answer
p700 is a general code to tell u that the tranny computer has a code in it.  U will need a better scanner to get those codes to start with. as for the running part  there is way to many different things that could have been done wrong  or on the used motor that is bad  U will need to have some one look at it first hand  I cant do anything like that over the internet sorry.