Yes, it will make a difference.

You will get fresh air into the exhaust mixture.

This air will cause the O2 sensor to indicate to the ECU that the engine is
running lean, and it will signal the fuel injectors to remain open longer.

This mean more fuel injected into the cylinders, and a faster idle.

IMHO.

Marshall Ruskin
84 Westy
----- Original Message -----
From: "ssmilby" <ssmilby@EMAIL.MSN.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, March 23, 2002 09:04 PM
Subject: high idol

This is driving me crazy!!!
My 85 will not idol below 1300 rpm's. The idol stop screw is all the way
bottomed out and I have checked the timing repeatedly.
There is one thing that might be messing with me. There is a hole in my
muffler before the oxygen sensor.  Would that make a difference??

Thanks in advance

Mark
85 Westi (1 week old)