88 caravan will not stay running

Put in new fuel pressure reg. and now will not stay running, with test guage on fuel line, I have good fuel press. with key off, and running, I can only keep it running by giving the throttle a good wide open at start-up, and keeping my foot on the accel. to keep the throttle open a lot, dies instantly when I let off the throttle. Because of this it also has new AIS, TPS, MAP, O2 sensors and still dies. I can hear the fuel pump running, as I stated the fuel pressure is good.

Has me baffled, it will not throw a single code. None. Gives a 55, (everything OK-end), and that's it.

I am the only owner, so this has me baffled also. On this 3.0l v-6, if idle is normal, and you pull the pvc hose off the air horn, it will kill the motor. Now, if I disconnect the pvc (more air into the air horn-engine), the van will stay running.
Also, I think it is way to running way to rich, getting a lot of black out the pipe.

I have checked (at least I thought or think) everything, no vac leaks, no sensor unpluged, wiring, hoses connected.
I am beginning to think it is mechanical, which means the van does not warrant anymore money spent, time to get rid
of it. I do have within specs though, good compression, and does not burn any oil.

Anyone, want to venture a guess. Our 3rd car, but is our basic hauler for our labs, and anything being done around property. Man, I hate to give it up.

Thanks Bob

Does not sound like a mechanical problem to me, unless your timing is way out of whack. If you've got access to a multi-tester or voltmeter I'd try the the test outlined in the links below - costs nothing to check except for time and fuel:

http://www.automotiveforums.com/vbulletin/showthread.php?t=419359

http://www.automotiveforums.com/vbulletin/showthread.php?t=398005