PVC fumes kill O2 sensors as well as pollute the air with toxic gases. PVC WILL melt in under hood temps, a friend with a second gen Escort LX can attest to that. Amazing how his hose clamps kept coming loose and the PVC kept changing shape in the summer time.

http://www.bnmotorsports.com "And I will strike down upon thee with great vengeance and furious anger those who attempt to poison and destroy my CEG brothers. And you will know I am the Moderator when I lay my vengeance upon you."