Generating env mapping tex coords

I am using glTexGen to generate my environment mapping textures coordinates.
Do i need to supply some tex coords anyway?
I have noticed that my rendering is behaving strangely when i don’t.
Thanx.

No.

What texGen do you use ?
Make sure you have texGen enabled.
Check normals.Do you scale
model view matrix?
Disable texture coord array.
Post here some code.