'97 Astro doesn't like moisture..?

I replaced: Coil, cap, rotor, plugs, and a few other things. If I let the van sit for more than 4-5 days, or if it's wet outside (high humidity or rain), I have a helluva time getting it started. Crank for up to 5-10 min as it fires and fires, but won't start. Basically just like it has a soaking wet cap/rotor, but it doesn't. Then, it'll miss, studder, and sometimes just plain die until I drive it for 5-10 minutes.. And, sometimes, it'll pop and backfire.. Then it clears up immediately like it was some ECM glitch or something and runs fine for days.. It's driving me nuts! Any ideas? Regulator? MAF? I'm lost at this point!

Any error codes?

No codes.. It used to throw a code when the EGR was bad.. But that's been it..

Have you checked the fuel pressure?

I just put a fuel pump in it a few months ago. I did two vehicles at the same time and I don't remember which pressure was which now.. But I'm pretty sure the van was at like 46 running.. But, I had this problem off and on before I put a pump in too.. It didn't make any difference.. It's almost like I'm either gulping fuel, or losing it.. It's very random and very strange..

you may have a leaking injector or fuel inlet. These motors are bad about that. Inside the intake manifold are a bunch of PLASTIC fuel lines. Your fuel pressure should rise to 60 PSI at key on and hold pressure with the key on and engine off. If it drops then Bingo. You have a leak somewhere. I had an inlet pipe leaking on mine last week. 50 bucks for a set of send and return lines and 3 hours of wrenching and she's golden.

Your system is very different from the '97. There are no nylon fuel pressure and return lines from 96 on.

The fuel pressure regulator is under the upper intake and the diaprhagm may be leaking fuel into the intake. This would explain why it runs rough once you get it started. I agree that a fuel pressure leak down test should be performed.

I'm probably gonna try a leakdown test on it at some point soon.. But, I'm really thinking this is some kind of electronic issue. It just, all of a sudden, smooths out most of the time. When it does, it's like the computer takes over and resets some stuff, the idle goes up quite a bit, then just drops down nice and smooth. It still runs a little rough under load for a bit of driving, then quits all that garbage and runs mint.. I'm gonna start going through some grounds and other connections and see if I find anything..

I am not trying yo hijack this thread, but is the burping, belching skipping misfires that my Astro exhibits due to fuel issues????????/ It seems or shall I say FEELS like electrical or igintion related.... that is what I have been chasing so far..