weird issue

Ok well this is the deal.

I am sitting in the local auto car wash and happily watching the dirt fall to the floor when all of a sudden the Blazer starts to idle VERY rough, almost to the point of dying.

It does this until the carwash has long since stopped and I am driving out of the parking lot.

After that its back to the nice gentle purr. Never again to do it until the next trip to the car wash.

My ???? to all of you is, What would cause this? Like I said the only time it does it is sitting in the wash no other time what-so-ever.

Any thoughts???

Been there. I use to have a Firebird that did the same thing. I modified(hacked) the filter box. When the prayer in the car wash would get to the area of the filter, the car would start to idle rough. It's moisture getting sucked into the intake. Do you have a modified or upgraded intake?

This could be the problem.

or distributor cap or plug wires are bad....or both
especially if you got the undercarrage spray

Ok well this is the deal.

I am sitting in the local auto car wash and happily watching the dirt fall to the floor when all of a sudden the Blazer starts to idle VERY rough, almost to the point of dying.

It does this until the carwash has long since stopped and I am driving out of the parking lot.

After that its back to the nice gentle purr. Never again to do it until the next trip to the car wash.

My ???? to all of you is, What would cause this? Like I said the only time it does it is sitting in the wash no other time what-so-ever.

Any thoughts???

Second the opinion on the Distributor and Wires. Check for holes, cracks etc. in the cap and for cracks etc. in the wires. You can also pull the cap off and look for moisture inside of the cap and in the distribtor.