2000 winstar van stalls

i have a 2000 windstar i replaced the intak manifold gaskets and the isolaster bolts. cause it it was chugging and bucking due to egr ports clogged. so i did that van runs fine for a few min then the idle drops down and the van dies out. i replaced the coil pack and the fuel filter helped a lil butnot much. im thinkin it has a vacc leak. so im goin out today and looking at the lines and replacing a few but idk wat it is. got any ideas? i dont have a fuel presure tester or voltage tester so i cant do that. it runs fine for a lil then rpms drop then dies out.

First thing that I do when something goes wrong after I have been working on my vehicle is to carefully go over what I have done.
With that in mind.....I would be looking for a vaccum leak....or something that did not get connected back up.

When it tries to stall....does slightly pressing the accellerator help?
If it does....look into the Idle Air Control (IAC) valve that is mounted to the side of the throttle body.
Do not rev the motor trying to find out the problem.....just a gentle press.

It sounds like it could be a vaccum leak that gets worse when the motor warms up....which would lead you to the upper intake manifold gaskets.......so if you do not find something, you might look into the upper intake manifold assembly process......for something like a loose bolt that you might have missed.
Do NOT overtighten the bolts......just check them (back off slightly and re-tighten each one).