Chevy & GMC Vans

Hi Folks,
I've been a pretty good mechanic on older vehicles for fifty years, but I have no idea what to do or where to start on my "New To Me" Astro Van, that I just bought to haul my band around town. I want to go through everything that I can in one pull of the doghouse. Here's what I've got:

1991 Base model Astro cargo van, 80,000 miles with 4.3 engine, automatic transmission, AC and manual windows, mirrors, etc. No leaks and all except the cruise control functions as it should. Sometimes it "stumbles" a little when accelerating from a stop and also seems to stumble after each upshift and on other various occasions. Also, while stopped, in gear, the engine will randomly stumble/cough/hiccup (or what ever you want to call it) and then the RPM increases for a split second, as it catches. It has not yet stalled or stopped.

My initial plan is to remove the doghouse and replace:

A) Spark plugs
B) Distributor cap, rotor & wires.
C) All filters I can find, along with the PCV valve
D) Inspect/replace all vacuum hoses that are changeable. One concern is that there may be some of those silly "harder" plastic vacuum lines that aren't intended to be easily replaced!
E) While I have no idea which computer/engine management system this has or any of the "alphabet soup" identifying it, I really want to learn how to test, check and/or replace any and all stuff pertaining to proper engine and transmission operation.

My inclination to do this all myself is not just to save a few $$$ (though that isn't a bad thing), but rather to make sure it gets done right and all the "I's" are dotted and "T's" are crossed! I am always leary to have anyone else "FIX" my stuff, as there are so many incompetent workmen out there!

Any and all help identifying what I'm working with and my best courses of action , would be much appreciated!

Thanks In Advance,
Gene

I too have been a mechanic for 50 years. These new computer operated vehicles have been a challenge. I would suggest you index the distributor housing to the manifold and the rotor to the housing. The reason being you should pull the distributor to check the wear on the gear. Premature wear of these gears is a common problem. Also check for excessive wear on the bushings. The index marks will be a big help in replacing the distributor.

Hey Smiliesafari,
It's nice to see a reply. I would be surprised to see distributor wear in 80,000 miles, but you're not the first to suggest a distributor issue, however for different issues than what you allude to. It sure can't hurt to check it and replacements seem to be fairly inexpensive and plentiful, even in upgraded "billet" formats.
Thanks Again,
Gene

for cheap insurance throw a new coil in it and keep the old one as a spare. They seem to die at random then work perfectly for days before they die again.

The occasional stumble in mine has been pinpointed to the MAP sensor. Its doesnt trip a code just makes it stumble every so often ( so live with it )

Where did you find an older van with such low miles ?

Listed on Craigslist with the title "1991 Astro Van, $300, No Title!" I'm sure the no title scared everyone off, as they only had three calls in three weeks. Turns out they actually have the title, just not signed. The older gentleman, now 88, bought it in 93 for $8,000 cash and never thought about the title, until they tried to sell it to CAR MAX, who wouldn't take it, due to the unsigned title. The dealer in So Cal that they bought it from is no longer in business, so they've already sent a registered/certified letter and form to the former business address, that will come back, unopened. The key here is to leave the letter sealed and let DMV open it and they will issue a new title. The old guy only used it for his "occasional" carpenter/home handyman business. I'm guessing he only worked a couple days a week and stayed close to home.

There are many things "jerry rigged" ala home handy man style, like loose, sloppy outer mirrors "FIXED" by jamming screws into the gaps and snipping off the heads, the wrong vacuum reservoir just kinda danglin' by a screw near the master cylinder and the fuel vapor canister replaced with a non original unit, while leaving the old one still in place! [-X Another big tell is that even though the sizes are correct there aren't two matching tires on it anywhere! I've seen this/been there kinda stuff before and it simply indicates that this van needs to be gone through from stem to stern, with a fine toothed comb and I will likely end up with a great truck!

Thanks,
Gene