My '87 was acting something like yours when my AFM was bad. The carbon
trace on the circuit board inside it had worn through and the ECU
wasn't getting the correct signals at idle. When it was warm it would
idle, but rough. I shifted the circuit board so that the wiper would
hit a fresh part of the carbon and now the van runs great. An O2
sensor can also cause problems. Try unplugging it to see if the van
will run better that way.

 Also, something that caused me trouble for a while was the connector
for the O2 sensor. There is a single connector where you plug the O2
sensor into the wiring harness. On the harness side, there is a green
shielded cable. When I pulled the rubber boot back off of it, I saw
that the grounded shield conductors were touching the main conductor.
That made for some real bad running, and it was intermittent, so it
took me a while to find it.

Finally, I don't think that our '87 vans have the air enrichment valve
that Stuart was talking about. We do have an idle stabilizer valve,
but it isn't heated and it doesn't bypass the AFM. It is controlled by
a black box under the right tail light. It can also cause idle
problems (high or low), but you should still be able to keep the van
running. My van will run OK with the idle stabilizer unplugged, but
the idle is a little slower.

On Mon, 5 Jun 2000 14:00:38 EDT, Mark Smith <CyrusWV@AOL.COM> wrote:

>Dear list,
>
>My 87 GL is exhibiting the following symptoms upon cold startup or after
>being parked for several hours. Anyone familiar with these symtoms? Your help
>will be greatly appreciated.
>
>It starts easily and idles smoothly at 1000 rpm for 20 to 30     seconds.
>Then it starts missing slightly and gradually worsens
>until the engine dies after another 20 to 30 seconds.
>
>The engine easily restarts each time it dies and repeats the above process
>until the temperature guage gets just below the warning light, afterwhich it
>runs perfectly. Trying to keep the revs up slightly does not help.
>
>It usually requires 10 or 12 startups and 10 or more minutes to get past this
>problem. The bus runs beautifully after its warm and does not have this
>problem after parking for up to 2 hours once the engine is warm.
>
>I have relaced the ignition wires, spark plugs, and the blue temperature
>switch located on the thermostat housing. I have ordered a new O2 sensor to
>install this week. So far nothing has helped my problem. Any ideas?
>
>Thanks for your help.
>
>Mark Smith
>87GL
>"Jimmy Joe"

--
Brad Snyder - bsnyder@enter.net
http://www.enter.net/~bsnyder