surging and dying

[cole2099]

I have a 1999 van when you pull up our steep driveway and let off the gas it dies.Also when its been driven a while and you shut it off then go to start it again it doesnt know where to idle at it ranges from 300 to 1200 rpm,kind of surges back and forth for about 15 to 20 seconds until it stabalizes. I also discoved on a trip to higher elevations around 8000 feet it does that same surging thing and will die.when you step on the gas it seems to run fine and no check engine lights come on. Anyone had a similar problem? Thanks

[94 Jimmy]

How many miles do you have on your van, when did you change the spark plugs and oxygen sensor last?
The oxygen sensor will drift as they age and can cause some strange things to happen.
You might try cleaning the throttle body especially around the Idle Speed Control (IAC) port just inside the body after the throttle plate.
Also the the Mass Air and Manifold Vacuum sensors, check to see that bugs and stuff havent gotten by the air cleaner and clogged them up. They are in the plastic section of the intake between the air cleaner and the throttle body.
These vehicles have a problem with the EGR valve, it can get stuck open by pieces of carbon that form in the exhaust port feeding the valve. This can also cause poor performance and rough running.
In general this is a shotgun process of checking everything that you can get at, unfortunately it's hard to get at some things.
Good luck, let us know what you find
94