We need way more information to start troubleshooting, can you fill out a profile with current mods, and a background on the issue(when did it start happening, have you done anything to troubleshoot? eg replacing parts ect)..

Just did an engine swap on my 97 eclipse hat with an 95/96 engine. Did all the proper adjustments to make the conversion work. The car started multiple time and stayed running. Went to go start it again the next day now it starts but only idles for a few seconds and then cuts back off.

Again, there are a plethora of variables to consider for this issue, your best bet is to create a profile with all of this information(How about the swap, is this a 4G63T or a 420a?) Did you replace all timing components, do you have DSMlink if its a 4G63T? A profile will be the quickest way to get help now and moving forward.

Right now your guess is as good as ours..

You have DSMLink? Since it ran WITH the engine swap, i am assuming you accounted for the different cam sensor(i'm rusty, forgive me). I would go with the standard troubleshooting method on a IC engine: Fuel, Spark, Compression. You sound like you have a fuel delivery issue. That is a wild ass guess with zero info though

Is it out of gas?
Fuel pump come on?
Fuel pressure to the rail?

Just a guess, but it sounds like a maf issue.

Like said before, we need more details, especially if things were swapped.